1.
Oxide minerals
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The oxide mineral class includes those minerals in which the oxide anion is bonded to one or more metal ions. The hydroxide bearing minerals are typically included in the oxide class, the minerals with complex anion groups such as the silicates, sulfates, carbonates and phosphates are classed separately. This list uses it to modify the Classification of Nickel–Strunz,00 Clinobirnessite*,00 Kleberite*,00 Chubutite*,00 Struverite
2.
Chemical formula
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These are limited to a single typographic line of symbols, which may include subscripts and superscripts. A chemical formula is not a name, and it contains no words. Although a chemical formula may imply certain simple chemical structures, it is not the same as a full chemical structural formula. Chemical formulas can fully specify the structure of only the simplest of molecules and chemical substances, the simplest types of chemical formulas are called empirical formulas, which use letters and numbers indicating the numerical proportions of atoms of each type. Molecular formulas indicate the numbers of each type of atom in a molecule. For example, the formula for glucose is CH2O, while its molecular formula is C6H12O6. This is possible if the relevant bonding is easy to show in one dimension, an example is the condensed molecular/chemical formula for ethanol, which is CH3-CH2-OH or CH3CH2OH. For reasons of structural complexity, there is no condensed chemical formula that specifies glucose, chemical formulas may be used in chemical equations to describe chemical reactions and other chemical transformations, such as the dissolving of ionic compounds into solution. A chemical formula identifies each constituent element by its chemical symbol, in empirical formulas, these proportions begin with a key element and then assign numbers of atoms of the other elements in the compound, as ratios to the key element. For molecular compounds, these numbers can all be expressed as whole numbers. For example, the formula of ethanol may be written C2H6O because the molecules of ethanol all contain two carbon atoms, six hydrogen atoms, and one oxygen atom. Some types of compounds, however, cannot be written with entirely whole-number empirical formulas. An example is boron carbide, whose formula of CBn is a variable non-whole number ratio with n ranging from over 4 to more than 6.5. When the chemical compound of the consists of simple molecules. These types of formulas are known as molecular formulas and condensed formulas. A molecular formula enumerates the number of atoms to reflect those in the molecule, so that the formula for glucose is C6H12O6 rather than the glucose empirical formula. However, except for very simple substances, molecular chemical formulas lack needed structural information, for simple molecules, a condensed formula is a type of chemical formula that may fully imply a correct structural formula. For example, ethanol may be represented by the chemical formula CH3CH2OH
3.
Crystal system
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In crystallography, the terms crystal system, crystal family and lattice system each refer to one of several classes of space groups, lattices, point groups or crystals. Informally, two crystals are in the crystal system if they have similar symmetries, though there are many exceptions to this. Space groups and crystals are divided into seven crystal systems according to their point groups, five of the crystal systems are essentially the same as five of the lattice systems, but the hexagonal and trigonal crystal systems differ from the hexagonal and rhombohedral lattice systems. The six crystal families are formed by combining the hexagonal and trigonal crystal systems into one hexagonal family, a lattice system is a class of lattices with the same set of lattice point groups, which are subgroups of the arithmetic crystal classes. The 14 Bravais lattices are grouped into seven lattice systems, triclinic, monoclinic, orthorhombic, tetragonal, rhombohedral, hexagonal, in a crystal system, a set of point groups and their corresponding space groups are assigned to a lattice system. Of the 32 point groups that exist in three dimensions, most are assigned to only one system, in which case both the crystal and lattice systems have the same name. However, five point groups are assigned to two systems, rhombohedral and hexagonal, because both exhibit threefold rotational symmetry. These point groups are assigned to the crystal system. In total there are seven crystal systems, triclinic, monoclinic, orthorhombic, tetragonal, trigonal, hexagonal, a crystal family is determined by lattices and point groups. It is formed by combining crystal systems which have space groups assigned to a lattice system. In three dimensions, the families and systems are identical, except the hexagonal and trigonal crystal systems. In total there are six families, triclinic, monoclinic, orthorhombic, tetragonal, hexagonal. Spaces with less than three dimensions have the number of crystal systems, crystal families and lattice systems. In one-dimensional space, there is one crystal system, in 2D space, there are four crystal systems, oblique, rectangular, square and hexagonal. The relation between three-dimensional crystal families, crystal systems and lattice systems is shown in the table, Note. To avoid confusion of terminology, the term trigonal lattice is not used, if the original structure and inverted structure are identical, then the structure is centrosymmetric. Still, even for non-centrosymmetric case, inverted structure in some cases can be rotated to align with the original structure and this is the case of non-centrosymmetric achiral structure. If the inverted structure cannot be rotated to align with the structure, then the structure is chiral
4.
Orthorhombic crystal system
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In crystallography, the orthorhombic crystal system is one of the 7 crystal systems. All three bases intersect at 90° angles, so the three lattice vectors remain mutually orthogonal, there are two orthorhombic Bravais lattices in two dimensions, Primitive rectangular and centered rectangular. The primitive rectangular lattice can also be described by a centered rhombic unit cell, there are four orthorhombic Bravais lattices, primitive orthorhombic, base-centered orthorhombic, body-centered orthorhombic, and face-centered orthorhombic. In this axis setting, the primitive and base-centered lattices interchange in centering type, crystal structure Overview of all space groups Hurlbut, Cornelius S. Klein, Cornelis. Hahn, Theo, ed. International Tables for Crystallography, Volume A, Space Group Symmetry
5.
Crystallographic point group
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For a periodic crystal, the group must also be consistent with maintenance of the three-dimensional translational symmetry that defines crystallinity. The macroscopic properties of a crystal would look exactly the same before, in the classification of crystals, each point group is also known as a crystal class. There are infinitely many three-dimensional point groups, however, the crystallographic restriction of the infinite families of general point groups results in there being only 32 crystallographic point groups. These 32 point groups are one-and-the same as the 32 types of morphological crystalline symmetries derived in 1830 by Johann Friedrich Christian Hessel from a consideration of observed crystal forms, the point groups are denoted by their component symmetries. There are a few standard notations used by crystallographers, mineralogists, for the correspondence of the two systems below, see crystal system. In Schoenflies notation, point groups are denoted by a symbol with a subscript. The symbols used in crystallography mean the following, Cn indicates that the group has a rotation axis. Cnh is Cn with the addition of a plane perpendicular to the axis of rotation. Cnv is Cn with the addition of n mirror planes parallel to the axis of rotation, s2n denotes a group that contains only a 2n-fold rotation-reflection axis. Dn indicates that the group has a rotation axis plus n twofold axes perpendicular to that axis. Dnh has, in addition, a plane perpendicular to the n-fold axis. Dnd has, in addition to the elements of Dn, mirror planes parallel to the n-fold axis, the letter T indicates that the group has the symmetry of a tetrahedron. Td includes improper rotation operations, T excludes improper rotation operations, the letter O indicates that the group has the symmetry of an octahedron, with or without improper operations. Due to the crystallographic restriction theorem, n =1,2,3,4, d4d and D6d are actually forbidden because they contain improper rotations with n=8 and 12 respectively. The 27 point groups in the table plus T, Td, Th, O, an abbreviated form of the Hermann–Mauguin notation commonly used for space groups also serves to describe crystallographic point groups. Group names are Molecular symmetry Point group Space group Point groups in three dimensions Crystal system Point-group symbols in International Tables for Crystallography,12.1, pp. 818-820 Names and symbols of the 32 crystal classes in International Tables for Crystallography. 10.1, p.794 Pictorial overview of the 32 groups Point Groups - Flow Chart Inorganic Chemistry Group Theory Practice Problems
6.
H-M symbol
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In geometry, Hermann–Mauguin notation is used to represent the symmetry elements in point groups, plane groups and space groups. It is named after the German crystallographer Carl Hermann and the French mineralogist Charles-Victor Mauguin and this notation is sometimes called international notation, because it was adopted as standard by the International Tables For Crystallography since their first edition in 1935. Rotation axes are denoted by a number n —1,2,3,4,5,6,7,8, for improper rotations, Hermann–Mauguin symbols show rotoinversion axes, unlike Schoenflies and Shubnikov notations, where the preference is given to rotation-reflection axes. The rotoinversion axes are represented by the number with a macron. The symbol for a plane is m. The direction of the plane is defined as the direction of perpendicular to the face. Hermann–Mauguin symbols show symmetrically non-equivalent axes and planes, the direction of a symmetry element is represented by its position in the Hermann–Mauguin symbol. If a rotation axis n and a mirror plane m have the same direction, if two or more axes have the same direction, the axis with higher symmetry is shown. Higher symmetry means that the axis generates a pattern with more points, for example, rotation axes 3,4,5,6,7,8 generate 3-, 4-, 5-, 6-, 7-, 8-point patterns, respectively. Improper rotation axes 3,4,5,6,7,8 generate 6-, 4-, 10-, 6-, 14-, 8-point patterns, if both, the rotation and rotoinversion axes satisfy the previous rule, the rotation axis should be chosen. For example, 3/m combination is equivalent to 6, since 6 generates 6 points, and 3 generates only 3,6 should be written instead of 3/m. Analogously, in the case when both 3 and 3 axes are present,3 should be written, however we write 4/m, not 4/m, because both 4 and 4 generate four points. Finally, the Hermann–Mauguin symbol depends on the type of the group and these groups may contain only two-fold axes, mirror planes, and inversion center. These are the point groups 1 and 1,2, m, and 2/m, and 222, 2/m2/m2/m. If the symbol contains three positions, then they denote symmetry elements in the x, y, z direction, First position — primary direction — z direction, assigned to the higher-order axis. Second position — symmetrically equivalent secondary directions, which are perpendicular to the z-axis and these can be 2, m, or 2/m. Third position — symmetrically equivalent tertiary directions, passing between secondary directions and these can be 2, m, or 2/m. These are the crystallographic groups 3,32, 3m,3, and 32/m,4,422, 4mm,4, 42m, 4/m, and 4/m2/m2/m, and 6,622, 6mm,6, 6m2, 6/m, and 6/m2/m2/m
7.
Cleavage (crystal)
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Cleavage, in mineralogy, is the tendency of crystalline materials to split along definite crystallographic structural planes. Cleavage forms parallel to planes, Basal or pinacoidal cleavage occurs when there is only one cleavage plane. Mica also has basal cleavage, this is why mica can be peeled into thin sheets, cubic cleavage occurs on when there are three cleavage planes intersecting at 90 degrees. Halite has cubic cleavage, and therefore, when halite crystals are broken, octahedral cleavage occurs when there are four cleavage planes in a crystal. Octahedral cleavage is common for semiconductors, rhombohedral cleavage occurs when there are three cleavage planes intersecting at angles that are not 90 degrees. Prismatic cleavage occurs when there are two planes in a crystal. Dodecahedral cleavage occurs when there are six cleavage planes in a crystal, crystal parting occurs when minerals break along planes of structural weakness due to external stress or along twin composition planes. Parting breaks are very similar in appearance to cleavage, but only due to stress. Examples include magnetite which shows octahedral parting, the parting of corundum. Cleavage is a property traditionally used in mineral identification, both in hand specimen and microscopic examination of rock and mineral studies. As an example, the angles between the cleavage planes for the pyroxenes and the amphiboles are diagnostic. Crystal cleavage is of importance in the electronics industry and in the cutting of gemstones. Precious stones are generally cleaved by impact, as in diamond cutting, synthetic single crystals of semiconductor materials are generally sold as thin wafers which are much easier to cleave. Elemental semiconductors are diamond cubic, a group for which octahedral cleavage is observed. This means that some orientations of wafer allow near-perfect rectangles to be cleaved, most other commercial semiconductors can be made in the related zinc blende structure, with similar cleavage planes. Cleavage Mineral galleries, Mineral properties – Cleavage
8.
Fracture (mineralogy)
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In the field of mineralogy, fracture is the texture and shape of a rocks surface formed when a mineral is fractured. Minerals often have a highly distinctive fracture, making it a feature used in their identification. Fracture differs from cleavage in that the latter involves clean splitting along the planes of the minerals crystal structure. All minerals exhibit fracture, but when very strong cleavage is present, conchoidal fracture breakage that resembles the concentric ripples of a mussel shell. It often occurs in amorphous or fine-grained minerals such as flint, opal or obsidian, subconchoidal fracture is similar to conchoidal fracture, but with less significant curvature. Earthy fracture is reminiscent of freshly broken soil and it is frequently seen in relatively soft, loosely bound minerals, such as limonite, kaolinite and aluminite. Hackly fracture is jagged, sharp and not even and it occurs when metals are torn, and so is often encountered in native metals such as copper and silver. Splintery fracture comprises sharp elongated points and it is particularly seen in fibrous minerals such as chrysotile, but may also occur in non-fibrous minerals such as kyanite. Uneven fracture is a surface or one with random irregularities. It occurs in a range of minerals including arsenopyrite, pyrite and magnetite. Rudolf Duda and Lubos Rejl, Minerals of the World http, //www. galleries. com/minerals/property/fracture. htm
9.
Mohs scale of mineral hardness
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The Mohs scale of mineral hardness is a qualitative ordinal scale characterizing scratch resistance of various minerals through the ability of harder material to scratch softer material. Created in 1812 by German geologist and mineralogist Friedrich Mohs, it is one of several definitions of hardness in materials science, while greatly facilitating the identification of minerals in the field, the Mohs scale does not show how well hard materials perform in an industrial setting. Despite its lack of precision, the Mohs scale is highly relevant for field geologists, the Mohs scale hardness of minerals can be commonly found in reference sheets. Reference materials may be expected to have a uniform Mohs hardness, the Mohs scale of mineral hardness is based on the ability of one natural sample of mineral to scratch another mineral visibly. The samples of matter used by Mohs are all different minerals, Minerals are pure substances found in nature. Rocks are made up of one or more minerals, as the hardest known naturally occurring substance when the scale was designed, diamonds are at the top of the scale. The hardness of a material is measured against the scale by finding the hardest material that the material can scratch. For example, if material is scratched by apatite but not by fluorite. Scratching a material for the purposes of the Mohs scale means creating non-elastic dislocations visible to the naked eye, frequently, materials that are lower on the Mohs scale can create microscopic, non-elastic dislocations on materials that have a higher Mohs number. The Mohs scale is an ordinal scale. For example, corundum is twice as hard as topaz, the table below shows the comparison with the absolute hardness measured by a sclerometer, with pictorial examples. On the Mohs scale, a streak plate has a hardness of 7.0, using these ordinary materials of known hardness can be a simple way to approximate the position of a mineral on the scale. The table below incorporates additional substances that may fall between levels, Comparison between Hardness and Hardness, Mohs hardness of elements is taken from G. V, samsonov in Handbook of the physicochemical properties of the elements, IFI-Plenum, New York, USA,1968. The Hardness of Minerals and Rocks
10.
Lustre (mineralogy)
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Lustre or luster is the way light interacts with the surface of a crystal, rock, or mineral. The word traces its origins back to the latin lux, meaning light, a range of terms are used to describe lustre, such as earthy, metallic, greasy, and silky. Similarly, the term refers to a glassy lustre. A list of terms is given below. Lustre varies over a continuum, and so there are no rigid boundaries between the different types of lustre. The terms are frequently combined to describe types of lustre. Some minerals exhibit unusual optical phenomena, such as asterism or chatoyancy, a list of such phenomena is given below. Adamantine minerals possess a superlative lustre, which is most notably seen in diamond, such minerals are transparent or translucent, and have a high refractive index. Minerals with an adamantine lustre are uncommon, with examples being cerussite. Minerals with a degree of lustre are referred to as subadamantine, with some examples being garnet. Dull minerals exhibit little to no lustre, due to coarse granulations which scatter light in all directions, a distinction is sometimes drawn between dull minerals and earthy minerals, with the latter being coarser, and having even less lustre. Greasy minerals resemble fat or grease, a greasy lustre often occurs in minerals containing a great abundance of microscopic inclusions, with examples including opal and cordierite. Many minerals with a greasy lustre also feel greasy to the touch, metallic minerals have the lustre of polished metal, and with ideal surfaces will work as a reflective surface. Examples include galena, pyrite and magnetite, pearly minerals consist of thin transparent co-planar sheets. Light reflecting from these layers give them a lustre reminiscent of pearls, such minerals possess perfect cleavage, with examples including muscovite and stilbite. Resinous minerals have the appearance of resin, chewing gum or plastic, a principal example is amber, which is a form of fossilized resin. Silky minerals have an arrangement of extremely fine fibres, giving them a lustre reminiscent of silk. Examples include asbestos, ulexite and the satin spar variety of gypsum, a fibrous lustre is similar, but has a coarser texture
11.
Streak (mineralogy)
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The streak of a mineral is the color of the powder produced when it is dragged across an un-weathered surface. If no streak seems to be made, the streak is said to be white or colorless. Streak is particularly important as a diagnostic for opaque and colored materials and it is less useful for silicate minerals, most of which have a white streak or are too hard to powder easily. The apparent color of a mineral can vary widely because of impurities or a disturbed macroscopic crystal structure. Small amounts of an impurity that strongly absorbs a particular wavelength can radically change the wavelengths of light that are reflected by the specimen, and thus change the apparent color. However, when the specimen is dragged to produce a streak, it is broken into randomly oriented microscopic crystals, the surface across which the mineral is dragged is called a streak plate, and is generally made of unglazed porcelain tile. In the absence of a plate, the unglazed underside of a porcelain bowl or vase or the back of a glazed tile will work. Sometimes a streak is more easily or accurately described by comparing it with the streak made by another streak plate. Because the trail left behind results from the mineral being crushed into powder, in case of harder minerals, the color of the powder can be determined by filing or crushing with a hammer a small sample, which is then usually rubbed on a streak plate. Most minerals that are harder have a white streak. Some minerals leave a similar to their natural color, such as cinnabar. Other minerals leave surprising colors, such as fluorite, which always has a streak, although it can appear in purple, blue, yellow. Hematite, which is black in appearance, leaves a red streak which accounts for its name, galena, which can be similar in appearance to hematite, is easily distinguished by its gray streak. Hamilton, W. R. Cambridge Guide to Minerals, Rocks, the Encyclopedia of Gemstones and Minerals. New York, Facts on File. p.251, physical Characteristics of Minerals, at Introduction to Mineralogy by Andrea Bangert What is Streak
12.
Specific gravity
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This page is about the measurement using water as a reference. For a general use of gravity, see relative density. See intensive property for the property implied by specific, Apparent specific gravity is the ratio of the weight of a volume of the substance to the weight of an equal volume of the reference substance. The reference substance is always water at its densest for liquids. Nonetheless, the temperature and pressure must be specified for both the sample and the reference, pressure is nearly always 1 atm. Temperatures for both sample and reference vary from industry to industry, in British beer brewing, the practice for specific gravity as specified above is to multiply it by 1000. Being a ratio of densities, specific gravity is a dimensionless quantity, Specific gravity varies with temperature and pressure, reference and sample must be compared at the same temperature and pressure or be corrected to a standard reference temperature and pressure. Substances with a gravity of 1 are neutrally buoyant in water. Those with SG greater than 1 are denser than water and will, disregarding surface tension effects and those with an SG less than 1 are less dense than water and will float on it. In scientific work, the relationship of mass to volume is expressed directly in terms of the density of the substance under study. It is in industry where specific gravity finds wide application, often for historical reasons. True specific gravity can be expressed mathematically as, S G true = ρ sample ρ H2 O where ρ sample is the density of the sample, the density of water varies with temperature and pressure as does the density of the sample. So it is necessary to specify the temperatures and pressures at which the densities or weights were determined and it is nearly always the case that measurements are made at 1 nominal atmosphere. For true specific gravity calculations, air pressure must be considered, temperatures are specified by the notation with T s representing the temperature at which the samples density was determined and T r the temperature at which the reference density is specified. For example, SG would be understood to mean that the density of the sample was determined at 20°C and of the water at 4°C. Taking into account different sample and reference temperatures, we note that, while S G H2 O =1.000000, it is also the case that S G H2 O =0.998203 /0.999840 =0.998363. Here, temperature is being specified using the current ITS-90 scale, on the previous IPTS-68 scale, the densities at 20 °C and 4 °C are 0.9982071 and 0.9999720 respectively, resulting in an SG value for water of 0.9982343. For example, in the industry, the Plato table lists sucrose concentration by weight against true SG
13.
Mineral
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A mineral is a naturally occurring chemical compound, usually of crystalline form and abiogenic in origin. A mineral has one specific chemical composition, whereas a rock can be an aggregate of different minerals or mineraloids, the study of minerals is called mineralogy. There are over 5,300 known mineral species, over 5,070 of these have been approved by the International Mineralogical Association, the silicate minerals compose over 90% of the Earths crust. The diversity and abundance of species is controlled by the Earths chemistry. Silicon and oxygen constitute approximately 75% of the Earths crust, which translates directly into the predominance of silicate minerals, minerals are distinguished by various chemical and physical properties. Differences in chemical composition and crystal structure distinguish the various species, changes in the temperature, pressure, or bulk composition of a rock mass cause changes in its minerals. Minerals can be described by their various properties, which are related to their chemical structure. Common distinguishing characteristics include crystal structure and habit, hardness, lustre, diaphaneity, colour, streak, tenacity, cleavage, fracture, parting, more specific tests for describing minerals include magnetism, taste or smell, radioactivity and reaction to acid. Minerals are classified by key chemical constituents, the two dominant systems are the Dana classification and the Strunz classification, the silicate class of minerals is subdivided into six subclasses by the degree of polymerization in the chemical structure. All silicate minerals have a unit of a 4− silica tetrahedron—that is, a silicon cation coordinated by four oxygen anions. These tetrahedra can be polymerized to give the subclasses, orthosilicates, disilicates, cyclosilicates, inosilicates, phyllosilicates, other important mineral groups include the native elements, sulfides, oxides, halides, carbonates, sulfates, and phosphates. The first criterion means that a mineral has to form by a natural process, stability at room temperature, in the simplest sense, is synonymous to the mineral being solid. More specifically, a compound has to be stable or metastable at 25 °C, modern advances have included extensive study of liquid crystals, which also extensively involve mineralogy. Minerals are chemical compounds, and as such they can be described by fixed or a variable formula, many mineral groups and species are composed of a solid solution, pure substances are not usually found because of contamination or chemical substitution. Finally, the requirement of an ordered atomic arrangement is usually synonymous with crystallinity, however, crystals are also periodic, an ordered atomic arrangement gives rise to a variety of macroscopic physical properties, such as crystal form, hardness, and cleavage. There have been recent proposals to amend the definition to consider biogenic or amorphous substances as minerals. The formal definition of an approved by the IMA in 1995, A mineral is an element or chemical compound that is normally crystalline. However, if geological processes were involved in the genesis of the compound, Mineral classification schemes and their definitions are evolving to match recent advances in mineral science
14.
Iron
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Iron is a chemical element with symbol Fe and atomic number 26. It is a metal in the first transition series and it is by mass the most common element on Earth, forming much of Earths outer and inner core. It is the fourth most common element in the Earths crust, like the other group 8 elements, ruthenium and osmium, iron exists in a wide range of oxidation states, −2 to +6, although +2 and +3 are the most common. Elemental iron occurs in meteoroids and other low oxygen environments, but is reactive to oxygen, fresh iron surfaces appear lustrous silvery-gray, but oxidize in normal air to give hydrated iron oxides, commonly known as rust. Unlike the metals that form passivating oxide layers, iron oxides occupy more volume than the metal and thus flake off, Iron metal has been used since ancient times, although copper alloys, which have lower melting temperatures, were used even earlier in human history. Pure iron is soft, but is unobtainable by smelting because it is significantly hardened and strengthened by impurities, in particular carbon. A certain proportion of carbon steel, which may be up to 1000 times harder than pure iron. Crude iron metal is produced in blast furnaces, where ore is reduced by coke to pig iron, further refinement with oxygen reduces the carbon content to the correct proportion to make steel. Steels and iron alloys formed with metals are by far the most common industrial metals because they have a great range of desirable properties. Iron chemical compounds have many uses, Iron oxide mixed with aluminium powder can be ignited to create a thermite reaction, used in welding and purifying ores. Iron forms binary compounds with the halogens and the chalcogens, among its organometallic compounds is ferrocene, the first sandwich compound discovered. Iron plays an important role in biology, forming complexes with oxygen in hemoglobin and myoglobin. Iron is also the metal at the site of many important redox enzymes dealing with cellular respiration and oxidation and reduction in plants. A human male of average height has about 4 grams of iron in his body and this iron is distributed throughout the body in hemoglobin, tissues, muscles, bone marrow, blood proteins, enzymes, ferritin, hemosiderin, and transport in plasma. The mechanical properties of iron and its alloys can be evaluated using a variety of tests, including the Brinell test, Rockwell test, the data on iron is so consistent that it is often used to calibrate measurements or to compare tests. An increase in the content will cause a significant increase in the hardness. Maximum hardness of 65 Rc is achieved with a 0. 6% carbon content, because of the softness of iron, it is much easier to work with than its heavier congeners ruthenium and osmium. Because of its significance for planetary cores, the properties of iron at high pressures and temperatures have also been studied extensively
15.
Manganese
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Manganese is a chemical element with symbol Mn and atomic number 25. It is not found as an element in nature, it is often found in minerals in combination with iron. Manganese is a metal with important industrial metal alloy uses, particularly in stainless steels, by the mid-18th century, Swedish chemist Carl Wilhelm Scheele had used pyrolusite to produce chlorine. Scheele and others were aware that pyrolusite contained a new element, johan Gottlieb Gahn was the first to isolate an impure sample of manganese metal in 1774, which he did by reducing the dioxide with carbon. Manganese phosphating is used for rust and corrosion prevention on steel, ionized manganese is used industrially as pigments of various colors, which depend on the oxidation state of the ions. The permanganates of alkali and alkaline earth metals are powerful oxidizers, Manganese dioxide is used as the cathode material in zinc-carbon and alkaline batteries. In biology, manganese ions function as cofactors for a variety of enzymes with many functions. Manganese enzymes are essential in detoxification of superoxide free radicals in organisms that must deal with elemental oxygen. Manganese also functions in the complex of photosynthetic plants. The element is a trace mineral for all known living organisms but is a neurotoxin. In larger amounts, and apparently with far greater effectiveness through inhalation, Manganese is a silvery-gray metal that resembles iron. It is hard and very brittle, difficult to fuse, Manganese metal and its common ions are paramagnetic. Manganese tarnishes slowly in air and oxidizes like iron in water containing dissolved oxygen, naturally occurring manganese is composed of one stable isotope, 55Mn. Eighteen radioisotopes have been isolated and described, the most stable being 53Mn with a half-life of 3.7 million years, 54Mn with a half-life of 312.3 days, and 52Mn with a half-life of 5.591 days. All of the radioactive isotopes have half-lives of less than three hours, and the majority of less than one minute. Manganese also has three meta states, Manganese is part of the iron group of elements, which are thought to be synthesized in large stars shortly before the supernova explosion. 53Mn decays to 53Cr with a half-life of 3.7 million years, because of its relatively short half-life, 53Mn is relatively rare, produced by cosmic rays impact on iron. Manganese isotopic contents are combined with chromium isotopic contents and have found application in isotope geology
16.
Tantalum
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Tantalum is a chemical element with symbol Ta and atomic number 73. Previously known as tantalium, its name comes from Tantalus, a villain from Greek mythology, tantalum is a rare, hard, blue-gray, lustrous transition metal that is highly corrosion-resistant. It is part of the refractory metals group, which are used as minor components in alloys. The chemical inertness of tantalum makes it a substance for laboratory equipment. Its main use today is in tantalum capacitors in electronic equipment such as phones, DVD players, video game systems. Tantalum, always together with the chemically similar niobium, occurs in the minerals tantalite, columbite, tantalum was discovered in Sweden in 1802 by Anders Ekeberg. One year earlier, Charles Hatchett had discovered the element columbium and he decided to keep the name tantalum. After Friedrich Wöhler confirmed these results, it was thought that columbium and tantalum were the same element. The supposed element pelopium was identified as a mixture of tantalum and niobium. Further confirmation came from the Swiss chemist Jean Charles Galissard de Marignac, in 1866 and these discoveries did not stop scientists from publishing articles about the so-called ilmenium until 1871. De Marignac was the first to produce the form of tantalum in 1864. Early investigators had only been able to produce impure tantalum, wires made with metallic tantalum were used for light bulb filaments until tungsten replaced it in widespread use. The name tantalum was derived from the name of the mythological Tantalus, in the story, he had been punished after death by being condemned to stand knee-deep in water with perfect fruit growing above his head, both of which eternally tantalized him. Ekeberg wrote This metal I call tantalum, partly in allusion to its incapacity, when immersed in acid, to absorb any and be saturated. This method has been supplanted by solvent extraction from fluoride-containing solutions of tantalum, tantalum is dark, dense, ductile, very hard, easily fabricated, and highly conductive of heat and electricity. The metal is renowned for its resistance to corrosion by acids, in fact and it can be dissolved with hydrofluoric acid or acidic solutions containing the fluoride ion and sulfur trioxide, as well as with a solution of potassium hydroxide. Tantalums high melting point of 3017 °C is exceeded among the only by tungsten, rhenium and osmium for metals. Tantalum exists in two phases, alpha and beta
17.
Oxygen
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Oxygen is a chemical element with symbol O and atomic number 8. It is a member of the group on the periodic table and is a highly reactive nonmetal. By mass, oxygen is the third-most abundant element in the universe, after hydrogen, at standard temperature and pressure, two atoms of the element bind to form dioxygen, a colorless and odorless diatomic gas with the formula O2. This is an important part of the atmosphere and diatomic oxygen gas constitutes 20. 8% of the Earths atmosphere, additionally, as oxides the element makes up almost half of the Earths crust. Most of the mass of living organisms is oxygen as a component of water, conversely, oxygen is continuously replenished by photosynthesis, which uses the energy of sunlight to produce oxygen from water and carbon dioxide. Oxygen is too reactive to remain a free element in air without being continuously replenished by the photosynthetic action of living organisms. Another form of oxygen, ozone, strongly absorbs ultraviolet UVB radiation, but ozone is a pollutant near the surface where it is a by-product of smog. At low earth orbit altitudes, sufficient atomic oxygen is present to cause corrosion of spacecraft, the name oxygen was coined in 1777 by Antoine Lavoisier, whose experiments with oxygen helped to discredit the then-popular phlogiston theory of combustion and corrosion. One of the first known experiments on the relationship between combustion and air was conducted by the 2nd century BCE Greek writer on mechanics, Philo of Byzantium. In his work Pneumatica, Philo observed that inverting a vessel over a burning candle, Philo incorrectly surmised that parts of the air in the vessel were converted into the classical element fire and thus were able to escape through pores in the glass. Many centuries later Leonardo da Vinci built on Philos work by observing that a portion of air is consumed during combustion and respiration, Oxygen was discovered by the Polish alchemist Sendivogius, who considered it the philosophers stone. In the late 17th century, Robert Boyle proved that air is necessary for combustion, English chemist John Mayow refined this work by showing that fire requires only a part of air that he called spiritus nitroaereus. From this he surmised that nitroaereus is consumed in both respiration and combustion, Mayow observed that antimony increased in weight when heated, and inferred that the nitroaereus must have combined with it. Accounts of these and other experiments and ideas were published in 1668 in his work Tractatus duo in the tract De respiratione. Robert Hooke, Ole Borch, Mikhail Lomonosov, and Pierre Bayen all produced oxygen in experiments in the 17th and the 18th century but none of them recognized it as a chemical element. This may have been in part due to the prevalence of the philosophy of combustion and corrosion called the phlogiston theory, which was then the favored explanation of those processes. Established in 1667 by the German alchemist J. J. Becher, one part, called phlogiston, was given off when the substance containing it was burned, while the dephlogisticated part was thought to be its true form, or calx. The fact that a substance like wood gains overall weight in burning was hidden by the buoyancy of the combustion products
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Chemical element
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A chemical element or element is a species of atoms having the same number of protons in their atomic nuclei. There are 118 elements that have identified, of which the first 94 occur naturally on Earth with the remaining 24 being synthetic elements. There are 80 elements that have at least one stable isotope and 38 that have exclusively radioactive isotopes, iron is the most abundant element making up Earth, while oxygen is the most common element in the Earths crust. Chemical elements constitute all of the matter of the universe. The two lightest elements, hydrogen and helium, were formed in the Big Bang and are the most common elements in the universe. The next three elements were formed mostly by cosmic ray spallation, and are rarer than those that follow. Formation of elements with from 6 to 26 protons occurred and continues to occur in main sequence stars via stellar nucleosynthesis, the high abundance of oxygen, silicon, and iron on Earth reflects their common production in such stars. The term element is used for atoms with a number of protons as well as for a pure chemical substance consisting of a single element. A single element can form multiple substances differing in their structure, when different elements are chemically combined, with the atoms held together by chemical bonds, they form chemical compounds. Only a minority of elements are found uncombined as relatively pure minerals, among the more common of such native elements are copper, silver, gold, carbon, and sulfur. All but a few of the most inert elements, such as gases and noble metals, are usually found on Earth in chemically combined form. While about 32 of the elements occur on Earth in native uncombined forms. For example, atmospheric air is primarily a mixture of nitrogen, oxygen, and argon, the history of the discovery and use of the elements began with primitive human societies that found native elements like carbon, sulfur, copper and gold. Later civilizations extracted elemental copper, tin, lead and iron from their ores by smelting, using charcoal, alchemists and chemists subsequently identified many more, almost all of the naturally occurring elements were known by 1900. Save for unstable radioactive elements with short half-lives, all of the elements are available industrially, almost all other elements found in nature were made by various natural methods of nucleosynthesis. On Earth, small amounts of new atoms are produced in nucleogenic reactions, or in cosmogenic processes. Of the 94 naturally occurring elements, those with atomic numbers 1 through 82 each have at least one stable isotope, Isotopes considered stable are those for which no radioactive decay has yet been observed. Elements with atomic numbers 83 through 94 are unstable to the point that radioactive decay of all isotopes can be detected, the very heaviest elements undergo radioactive decay with half-lives so short that they are not found in nature and must be synthesized
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Columbite
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Columbite, also called niobite, niobite-tantalite and columbate, is a black mineral group that is an ore of niobium. It has a submetallic luster and a density and is a niobate of iron. This mineral group was first found in Haddam, Connecticut, in the United States and it forms a series with the tantalum-dominant analogue ferrotantalite and one with the manganese-dominant analogue manganocolumbite. The iron-rich member of the group is ferrocolumbite. Some tin and tungsten may be present in the mineral, yttrocolumbite is the yttrium-rich columbite with the formula O4. It is a mineral found in Mozambique. Columbite has the composition and crystal symmetry as tantalite. In fact, the two are grouped together as a semi-singular mineral series called columbite-tantalite or coltan in many mineral guides. However, tantalite has a greater specific gravity than columbite. Columbite is also similar to tapiolite. Those minerals have same chemical composition but different crystal symmetry, orthorhombic for columbite, the largest documented single crystal of columbite consisted of plates 6 mm thick measuring 76 cm ×61 cm. The occurrence of columbite in the United States was made known from a specimen presumably stemming from John Winthrop, first Governor of the Connecticut Colony and avid mineral collector. In 1801 Charles Hatchett discovered the element niobium in this specimen, which he named columbium in honour of Christopher Columbus, coltan List of minerals Texts on Wikisource, Columbite
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Coltan
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Coltan is a dull black metallic ore from which the elements niobium and tantalum are extracted. The niobium-dominant mineral in coltan is columbite, and the tantalum-dominant mineral is tantalite, tantalum from coltan is used to manufacture tantalum capacitors, used in electronic products. Coltan mining has been cited as helping to finance serious conflict, approximately 71% of global tantalum supply in 2008 was newly mined, 20% was from recycling, and the remainder was from tin slag and inventory. Tantalum minerals are mined in Australia, Brazil, Canada, Democratic Republic of Congo, China, Ethiopia, tantalum is also produced in Thailand and Malaysia as a by-product of tin mining and smelting. A significant reserve of coltan was discovered in 2009 in western Venezuela, in 2009 the Colombian government announced coltan reserves had been found in Colombias eastern provinces. Coltan is used primarily for the production of capacitors, used in many electronic devices. Many sources mention coltans importance in the production of mobile phones and it is also used in high-temperature alloys for air- and land-based turbines. The upsurge in electronic products over the past decade resulted in a peak in late 2000, in 2005, the price was still down at early 2000 levels. The United States Geological Survey estimated in 2009 that tantalum production capacity could meet global demand, countries rich in resources - such as Congo - have been affected by the phenomenon called resource curse. This is a phenomenon where countries that are rich in resources have worse economic development than countries that have fewer resources and this phenomenon does not allow for the Congolese to have a balanced and sustained development. It also indicates a relationship between the wealth of resources …and the likelihood of weak democratic development, corruption, and civil war. Such high levels of lead to great political instability and issues because whoever controls the assets can use them to their own benefit. These resources generate wealth for these people which they use to stay in power …either through legal means, when much of eastern Congo came under the control of Rwandan forces from the 1990s, Rwanda became a major exporter of coltan, benefiting from the weakness of the Congolese government. Coltan is made into a component for many products such as cell phones. The digital age has caused issues regarding power relations and violence between individuals from Congo and the rest of the world, an example of uneven power relations was in late 2000, when there was a great demand for the PlayStation 2. This demand caused the price of coltan to increase very quickly and after demand for the system fell. The price hike intensified violence in Eastern Congo, as the violence was being directed at everyday social production, because there is a growing need for new technologies, the demand for coltan is growing substantially. For Congolese, mining is the easiest source of income, because the work is consistent and it is laborious, as miners walk for days in the forest to the ore, scratch it with hand tools and pan it
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Tapiolite
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Tapiolite is a black mineral series that is an ore of niobium and tantalum. The tapiolite group includes tapiolite- or ferrotapiolite and tapiolite- or manganotapiolite, tapiolite- is by far the more common of the two. The minerals have a submetallic luster and a specific gravity with tapiolite-Fe having a higher specific gravity versus 7.72 for tapiolite-Mn. The mineral was named in 1863 after the forest god Tapio of Finnish mythology, tapiolite is very close to columbite and tantalite. Those minerals have the chemical composition, but different crystal symmetry orthorhombic for tantalite or columbite
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Tetragonal crystal system
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In crystallography, the tetragonal crystal system is one of the 7 crystal systems. Tetragonal crystal lattices result from stretching a cubic lattice along one of its vectors, so that the cube becomes a rectangular prism with a square base. There is only one tetragonal Bravais lattice in two dimensions, the square lattice, there are two tetragonal Bravais lattices, the simple tetragonal and the centered tetragonal. One might suppose stretching face-centered cubic would result in face-centered tetragonal, BCT is considered more fundamental, so that is the standard terminology. Crystal structure point groups Bravais lattices
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Transparency and translucency
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In the field of optics, transparency is the physical property of allowing light to pass through the material without being scattered. On a macroscopic scale, the photons can be said to follow Snells Law, in other words, a translucent medium allows the transport of light while a transparent medium not only allows the transport of light but allows for image formation. The opposite property of translucency is opacity, transparent materials appear clear, with the overall appearance of one color, or any combination leading up to a brilliant spectrum of every color. When light encounters a material, it can interact with it in different ways. These interactions depend on the wavelength of the light and the nature of the material, photons interact with an object by some combination of reflection, absorption and transmission. Some materials, such as glass and clean water, transmit much of the light that falls on them and reflect little of it. Many liquids and aqueous solutions are highly transparent, absence of structural defects and molecular structure of most liquids are mostly responsible for excellent optical transmission. Materials which do not transmit light are called opaque, many such substances have a chemical composition which includes what are referred to as absorption centers. Many substances are selective in their absorption of light frequencies. They absorb certain portions of the spectrum while reflecting others. The frequencies of the spectrum which are not absorbed are either reflected or transmitted for our physical observation and this is what gives rise to color. The attenuation of light of all frequencies and wavelengths is due to the mechanisms of absorption. Transparency can provide almost perfect camouflage for animals able to achieve it and this is easier in dimly-lit or turbid seawater than in good illumination. Many marine animals such as jellyfish are highly transparent, at the atomic or molecular level, physical absorption in the infrared portion of the spectrum depends on the frequencies of atomic or molecular vibrations or chemical bonds, and on selection rules. Nitrogen and oxygen are not greenhouse gases because there is no absorption because there is no molecular dipole moment. With regard to the scattering of light, the most critical factor is the scale of any or all of these structural features relative to the wavelength of the light being scattered. Primary material considerations include, Crystalline structure, whether or not the atoms or molecules exhibit the long-range order evidenced in crystalline solids, glassy structure, scattering centers include fluctuations in density or composition. Microstructure, scattering centers include internal surfaces such as boundaries, crystallographic defects
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Brazil
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Brazil, officially the Federative Republic of Brazil, is the largest country in both South America and Latin America. As the worlds fifth-largest country by area and population, it is the largest country to have Portuguese as an official language. Its Amazon River basin includes a vast tropical forest, home to wildlife, a variety of ecological systems. This unique environmental heritage makes Brazil one of 17 megadiverse countries, Brazil was inhabited by numerous tribal nations prior to the landing in 1500 of explorer Pedro Álvares Cabral, who claimed the area for the Portuguese Empire. Brazil remained a Portuguese colony until 1808, when the capital of the empire was transferred from Lisbon to Rio de Janeiro, in 1815, the colony was elevated to the rank of kingdom upon the formation of the United Kingdom of Portugal, Brazil and the Algarves. Independence was achieved in 1822 with the creation of the Empire of Brazil, a state governed under a constitutional monarchy. The ratification of the first constitution in 1824 led to the formation of a bicameral legislature, the country became a presidential republic in 1889 following a military coup détat. An authoritarian military junta came to power in 1964 and ruled until 1985, Brazils current constitution, formulated in 1988, defines it as a democratic federal republic. The federation is composed of the union of the Federal District, the 26 states, Brazils economy is the worlds ninth-largest by nominal GDP and seventh-largest by GDP as of 2015. A member of the BRICS group, Brazil until 2010 had one of the worlds fastest growing economies, with its economic reforms giving the country new international recognition. Brazils national development bank plays an important role for the economic growth. Brazil is a member of the United Nations, the G20, BRICS, Unasul, Mercosul, Organization of American States, Organization of Ibero-American States, CPLP. Brazil is a power in Latin America and a middle power in international affairs. One of the worlds major breadbaskets, Brazil has been the largest producer of coffee for the last 150 years and it is likely that the word Brazil comes from the Portuguese word for brazilwood, a tree that once grew plentifully along the Brazilian coast. In Portuguese, brazilwood is called pau-brasil, with the word brasil commonly given the etymology red like an ember, formed from Latin brasa and the suffix -il. As brazilwood produces a red dye, it was highly valued by the European cloth industry and was the earliest commercially exploited product from Brazil. The popular appellation eclipsed and eventually supplanted the official Portuguese name, early sailors sometimes also called it the Land of Parrots. In the Guarani language, a language of Paraguay, Brazil is called Pindorama
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Australia
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Australia, officially the Commonwealth of Australia, is a country comprising the mainland of the Australian continent, the island of Tasmania and numerous smaller islands. It is the worlds sixth-largest country by total area, the neighbouring countries are Papua New Guinea, Indonesia and East Timor to the north, the Solomon Islands and Vanuatu to the north-east, and New Zealand to the south-east. Australias capital is Canberra, and its largest urban area is Sydney, for about 50,000 years before the first British settlement in the late 18th century, Australia was inhabited by indigenous Australians, who spoke languages classifiable into roughly 250 groups. The population grew steadily in subsequent decades, and by the 1850s most of the continent had been explored, on 1 January 1901, the six colonies federated, forming the Commonwealth of Australia. Australia has since maintained a liberal democratic political system that functions as a federal parliamentary constitutional monarchy comprising six states. The population of 24 million is highly urbanised and heavily concentrated on the eastern seaboard, Australia has the worlds 13th-largest economy and ninth-highest per capita income. With the second-highest human development index globally, the country highly in quality of life, health, education, economic freedom. The name Australia is derived from the Latin Terra Australis a name used for putative lands in the southern hemisphere since ancient times, the Dutch adjectival form Australische was used in a Dutch book in Batavia in 1638, to refer to the newly discovered lands to the south. On 12 December 1817, Macquarie recommended to the Colonial Office that it be formally adopted, in 1824, the Admiralty agreed that the continent should be known officially as Australia. The first official published use of the term Australia came with the 1830 publication of The Australia Directory and these first inhabitants may have been ancestors of modern Indigenous Australians. The Torres Strait Islanders, ethnically Melanesian, were originally horticulturists, the northern coasts and waters of Australia were visited sporadically by fishermen from Maritime Southeast Asia. The first recorded European sighting of the Australian mainland, and the first recorded European landfall on the Australian continent, are attributed to the Dutch. The first ship and crew to chart the Australian coast and meet with Aboriginal people was the Duyfken captained by Dutch navigator, Willem Janszoon. He sighted the coast of Cape York Peninsula in early 1606, the Dutch charted the whole of the western and northern coastlines and named the island continent New Holland during the 17th century, but made no attempt at settlement. William Dampier, an English explorer and privateer, landed on the north-west coast of New Holland in 1688, in 1770, James Cook sailed along and mapped the east coast, which he named New South Wales and claimed for Great Britain. The first settlement led to the foundation of Sydney, and the exploration, a British settlement was established in Van Diemens Land, now known as Tasmania, in 1803, and it became a separate colony in 1825. The United Kingdom formally claimed the part of Western Australia in 1828. Separate colonies were carved from parts of New South Wales, South Australia in 1836, Victoria in 1851, the Northern Territory was founded in 1911 when it was excised from South Australia
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Canada
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Canada is a country in the northern half of North America. Canadas border with the United States is the worlds longest binational land border, the majority of the country has a cold or severely cold winter climate, but southerly areas are warm in summer. Canada is sparsely populated, the majority of its territory being dominated by forest and tundra. It is highly urbanized with 82 per cent of the 35.15 million people concentrated in large and medium-sized cities, One third of the population lives in the three largest cities, Toronto, Montreal and Vancouver. Its capital is Ottawa, and other urban areas include Calgary, Edmonton, Quebec City, Winnipeg. Various aboriginal peoples had inhabited what is now Canada for thousands of years prior to European colonization. Pursuant to the British North America Act, on July 1,1867, the colonies of Canada, New Brunswick and this began an accretion of provinces and territories to the mostly self-governing Dominion to the present ten provinces and three territories forming modern Canada. With the Constitution Act 1982, Canada took over authority, removing the last remaining ties of legal dependence on the Parliament of the United Kingdom. Canada is a parliamentary democracy and a constitutional monarchy, with Queen Elizabeth II being the head of state. The country is officially bilingual at the federal level and it is one of the worlds most ethnically diverse and multicultural nations, the product of large-scale immigration from many other countries. Its advanced economy is the eleventh largest in the world, relying chiefly upon its abundant natural resources, Canadas long and complex relationship with the United States has had a significant impact on its economy and culture. Canada is a country and has the tenth highest nominal per capita income globally as well as the ninth highest ranking in the Human Development Index. It ranks among the highest in international measurements of government transparency, civil liberties, quality of life, economic freedom, Canada is an influential nation in the world, primarily due to its inclusive values, years of prosperity and stability, stable economy, and efficient military. While a variety of theories have been postulated for the origins of Canada. In 1535, indigenous inhabitants of the present-day Quebec City region used the word to direct French explorer Jacques Cartier to the village of Stadacona, from the 16th to the early 18th century Canada referred to the part of New France that lay along the St. Lawrence River. In 1791, the area became two British colonies called Upper Canada and Lower Canada collectively named The Canadas, until their union as the British Province of Canada in 1841. Upon Confederation in 1867, Canada was adopted as the name for the new country at the London Conference. The transition away from the use of Dominion was formally reflected in 1982 with the passage of the Canada Act, later that year, the name of national holiday was changed from Dominion Day to Canada Day
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Colombia
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Colombia, officially the Republic of Colombia, is a transcontinental country largely situated in the northwest of South America, with territories in Central America. Colombia shares a border to the northwest with Panama, to the east with Venezuela and Brazil and to the south with Ecuador and it shares its maritime limits with Costa Rica, Nicaragua, Honduras, Jamaica, Haiti and the Dominican Republic. It is a unitary, constitutional republic comprising thirty-two departments, the territory of what is now Colombia was originally inhabited by indigenous peoples including the Muisca, the Quimbaya and the Tairona. The Spanish arrived in 1499 and initiated a period of conquest and colonization ultimately creating the Viceroyalty of New Granada, independence from Spain was won in 1819, but by 1830 the Gran Colombia Federation was dissolved. What is now Colombia and Panama emerged as the Republic of New Granada, the new nation experimented with federalism as the Granadine Confederation, and then the United States of Colombia, before the Republic of Colombia was finally declared in 1886. Since the 1960s the country has suffered from an asymmetric low-intensity armed conflict, Colombia is one of the most ethnically and linguistically diverse countries in the world, and thereby possesses a rich cultural heritage. Cultural diversity has also influenced by Colombias varied geography. The urban centres are located in the highlands of the Andes mountains. Colombian territory also encompasses Amazon rainforest, tropical grassland and both Caribbean and Pacific coastlines, ecologically, it is one of the worlds 17 megadiverse countries, and the most densely biodiverse of these per square kilometer. Colombia is a power and a regional actor with the fourth-largest economy in Latin America, is part of the CIVETS group of six leading emerging markets and is an accessing member to the OECD. Colombia has an economy with macroeconomic stability and favorable growth prospects in the long run. The name Colombia is derived from the last name of Christopher Columbus and it was conceived by the Venezuelan revolutionary Francisco de Miranda as a reference to all the New World, but especially to those portions under Spanish and Portuguese rule. The name was adopted by the Republic of Colombia of 1819. When Venezuela, Ecuador and Cundinamarca came to exist as independent states, New Granada officially changed its name in 1858 to the Granadine Confederation. In 1863 the name was changed, this time to United States of Colombia. To refer to country, the Colombian government uses the terms Colombia. Owing to its location, the present territory of Colombia was a corridor of early human migration from Mesoamerica, the oldest archaeological finds are from the Pubenza and El Totumo sites in the Magdalena Valley 100 km southwest of Bogotá. These sites date from the Paleoindian period, at Puerto Hormiga and other sites, traces from the Archaic Period have been found
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Vichada Department
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Vichada Department is a department of the Republic of Colombia in South America. Vichada is located in the plains of Colombia, in the Orinoquía Region within the Orinoco river basin bordering the Bolivarian Republic of Venezuela to the north. The department is the second largest in Colombia and scarcely populated in comparison to other departments, the department was previously a commissary established in 1913. The largest town and capital of the department is Puerto Carreño located in northeastern part of the department. The department is subdivided into four municipalities, Puerto Carreño, La Primavera, Santa Rosalía and it also contains 46 indigenous reserves and 6 communities. The department is located on the plains of Colombia known colloquially as the Llanos. The department is located to the margin of the Orinoco River. Part of the department lies on the Guiana Shield, soil lacks sediments due to the lack of alluvions from rivers coming from the Andes mountains. Climate in the department is predominantly hot and humid with a temperature of 28 °C throughout the year. In 1913 the government of Colombia created the commissary of Vichada, the town was named Puerto Carreño in honor of Pedro María Carreño, then acting Minister of Government. In August 1974, Puerto Carreño was elevated to the category of municipality by decree 1594 of that same year, on July 5,1991 Vichada was elevated to the category of department and Puerto Carreño as its capital. Cumaribo La Primavera Puerto Carreño Santa Rosalía Revista Semana, Será Vichada la tierra prometida, Government of Vichada official website Vichada Music llanera Territorial-Environmental Information System of Colombian Amazon SIAT-AC website
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Egypt
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Egypt, officially the Arab Republic of Egypt, is a transcontinental country spanning the northeast corner of Africa and southwest corner of Asia by a land bridge formed by the Sinai Peninsula. Egypt is a Mediterranean country bordered by the Gaza Strip and Israel to the northeast, the Gulf of Aqaba to the east, the Red Sea to the east and south, Sudan to the south, and Libya to the west. Across the Gulf of Aqaba lies Jordan, and across from the Sinai Peninsula lies Saudi Arabia, although Jordan and it is the worlds only contiguous Afrasian nation. Egypt has among the longest histories of any country, emerging as one of the worlds first nation states in the tenth millennium BC. Considered a cradle of civilisation, Ancient Egypt experienced some of the earliest developments of writing, agriculture, urbanisation, organised religion and central government. One of the earliest centres of Christianity, Egypt was Islamised in the century and remains a predominantly Muslim country. With over 92 million inhabitants, Egypt is the most populous country in North Africa and the Arab world, the third-most populous in Africa, and the fifteenth-most populous in the world. The great majority of its people live near the banks of the Nile River, an area of about 40,000 square kilometres, the large regions of the Sahara desert, which constitute most of Egypts territory, are sparsely inhabited. About half of Egypts residents live in areas, with most spread across the densely populated centres of greater Cairo, Alexandria. Modern Egypt is considered to be a regional and middle power, with significant cultural, political, and military influence in North Africa, the Middle East and the Muslim world. Egypts economy is one of the largest and most diversified in the Middle East, Egypt is a member of the United Nations, Non-Aligned Movement, Arab League, African Union, and Organisation of Islamic Cooperation. Miṣr is the Classical Quranic Arabic and modern name of Egypt. The name is of Semitic origin, directly cognate with other Semitic words for Egypt such as the Hebrew מִצְרַיִם, the oldest attestation of this name for Egypt is the Akkadian
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Europe
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Europe is a continent that comprises the westernmost part of Eurasia. Europe is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, yet the non-oceanic borders of Europe—a concept dating back to classical antiquity—are arbitrary. Europe covers about 10,180,000 square kilometres, or 2% of the Earths surface, politically, Europe is divided into about fifty sovereign states of which the Russian Federation is the largest and most populous, spanning 39% of the continent and comprising 15% of its population. Europe had a population of about 740 million as of 2015. Further from the sea, seasonal differences are more noticeable than close to the coast, Europe, in particular ancient Greece, was the birthplace of Western civilization. The fall of the Western Roman Empire, during the period, marked the end of ancient history. Renaissance humanism, exploration, art, and science led to the modern era, from the Age of Discovery onwards, Europe played a predominant role in global affairs. Between the 16th and 20th centuries, European powers controlled at times the Americas, most of Africa, Oceania. The Industrial Revolution, which began in Great Britain at the end of the 18th century, gave rise to economic, cultural, and social change in Western Europe. During the Cold War, Europe was divided along the Iron Curtain between NATO in the west and the Warsaw Pact in the east, until the revolutions of 1989 and fall of the Berlin Wall. In 1955, the Council of Europe was formed following a speech by Sir Winston Churchill and it includes all states except for Belarus, Kazakhstan and Vatican City. Further European integration by some states led to the formation of the European Union, the EU originated in Western Europe but has been expanding eastward since the fall of the Soviet Union in 1991. The European Anthem is Ode to Joy and states celebrate peace, in classical Greek mythology, Europa is the name of either a Phoenician princess or of a queen of Crete. The name contains the elements εὐρύς, wide, broad and ὤψ eye, broad has been an epithet of Earth herself in the reconstructed Proto-Indo-European religion and the poetry devoted to it. For the second part also the divine attributes of grey-eyed Athena or ox-eyed Hera. The same naming motive according to cartographic convention appears in Greek Ανατολή, Martin Litchfield West stated that phonologically, the match between Europas name and any form of the Semitic word is very poor. Next to these there is also a Proto-Indo-European root *h1regʷos, meaning darkness. Most major world languages use words derived from Eurṓpē or Europa to refer to the continent, in some Turkic languages the originally Persian name Frangistan is used casually in referring to much of Europe, besides official names such as Avrupa or Evropa
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Madagascar
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Madagascar, officially the Republic of Madagascar, and previously known as the Malagasy Republic, is an island country in the Indian Ocean, off the coast of Southeast Africa. The nation comprises the island of Madagascar, and numerous smaller peripheral islands, consequently, Madagascar is a biodiversity hotspot, over 90% of its wildlife is found nowhere else on Earth. The islands diverse ecosystems and unique wildlife are threatened by the encroachment of the growing human population. The first archaeological evidence for human foraging on Madagascar dates to 2000 BC, human settlement of Madagascar occurred between 350 BC and AD550 by Austronesian peoples arriving on outrigger canoes from Borneo. These were joined around AD1000 by Bantu migrants crossing the Mozambique Channel from East Africa, other groups continued to settle on Madagascar over time, each one making lasting contributions to Malagasy cultural life. The Malagasy ethnic group is divided into 18 or more sub-groups of which the largest are the Merina of the central highlands. Until the late 18th century, the island of Madagascar was ruled by an assortment of shifting sociopolitical alliances. Beginning in the early 19th century, most of the island was united and ruled as the Kingdom of Madagascar by a series of Merina nobles, the monarchy collapsed in 1897 when the island was absorbed into the French colonial empire, from which the island gained independence in 1960. The autonomous state of Madagascar has since undergone four major constitutional periods, since 1992, the nation has officially been governed as a constitutional democracy from its capital at Antananarivo. However, in an uprising in 2009, president Marc Ravalomanana was made to resign. Constitutional governance was restored in January 2014, when Hery Rajaonarimampianina was named president following a 2013 election deemed fair, Madagascar is a member of the United Nations, the Organisation Internationale de la Francophonie and the Southern African Development Community. Madagascar belongs to the group of least developed countries, according to the United Nations, Malagasy and French are both official languages of the state. The majority of the population adheres to traditional beliefs, Christianity, ecotourism and agriculture, paired with greater investments in education, health, and private enterprise, are key elements of Madagascars development strategy. As of 2017, the economy has been weakened by the 2009-2013 political crisis, in the Malagasy language, the island of Madagascar is called Madagasikara and its people are referred to as Malagasy. The islands appellation Madagascar is not of origin, but rather was popularized in the Middle Ages by Europeans. On St. Laurences Day in 1500, Portuguese explorer Diogo Dias landed on the island, polos name was preferred and popularized on Renaissance maps. At 592,800 square kilometres, Madagascar is the worlds 47th largest country, the country lies mostly between latitudes 12°S and 26°S, and longitudes 43°E and 51°E. Neighboring islands include the French territory of Réunion and the country of Mauritius to the east, as well as the state of Comoros, the nearest mainland state is Mozambique, located to the west
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Namibia
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Namibia, officially the Republic of Namibia, is a country in southern Africa whose western border is the Atlantic Ocean. It shares land borders with Zambia and Angola to the north, Botswana to the east and South Africa to the south, although it does not border Zimbabwe, a part of less than 200 metres of the Zambezi River separates the two countries. Namibia gained independence from South Africa on 21 March 1990, following the Namibian War of Independence. Its capital and largest city is Windhoek, and it is a state of the United Nations, the Southern African Development Community, the African Union. The dry lands of Namibia were inhabited since early times by the San, Damara, since about the 14th century, immigrating Bantu peoples arrived as part of the Bantu expansion. Since then the Bantu groups in total, known as the Ovambo people, have dominated the population of the country, in the late 19th century during European colonization, the German Empire established rule over most of the territory as a protectorate in 1884. It began to develop infrastructure and farming, and maintained this German colony until 1915, after the end of World War I, in 1920 the League of Nations mandated the country to the United Kingdom, under administration by South Africa. It imposed its laws, including racial classifications and rules, from 1948, with the National Party elected to power, South Africa applied apartheid also to what was known as South West Africa. In 1878 the Cape of Good Hope had annexed the port of Walvis Bay and the offshore Penguin Islands, following continued guerrilla warfare, South Africa installed an interim administration in Namibia in 1985. Namibia obtained full independence from South Africa in 1990, but Walvis Bay and the Penguin Islands remained under South African control until 1994. Namibia has a population of 2.1 million people and a stable multi-party parliamentary democracy, Agriculture, herding, tourism and the mining industry – including mining for gem diamonds, uranium, gold, silver, and base metals – form the basis of its economy. The large, arid Namib Desert has resulted in Namibia being overall one of the least densely populated countries in the world, Namibia enjoys high political, economic and social stability. The name of the country is derived from the Namib Desert, before its independence in 1990, the area was known first as German South-West Africa, then as South-West Africa, reflecting the colonial occupation by the Germans and the South Africans. The dry lands of Namibia were inhabited since early times by San, Damara, from about the 14th century, immigrating Bantu peoples arrived during the Bantu expansion from central Africa. From the late 18th century onwards, Oorlam people from Cape Colony crossed the Orange River and their encounters with the nomadic Nama tribes were largely peaceful. The missionaries accompanying the Oorlam were well received by them, the right to use waterholes, on their way further northwards, however, the Oorlam encountered clans of the Herero at Windhoek, Gobabis, and Okahandja, who resisted their encroachment. The Nama-Herero War broke out in 1880, with hostilities ebbing only after the German Empire deployed troops to the places and cemented the status quo among the Nama, Oorlam. The first Europeans to disembark and explore the region were the Portuguese navigators Diogo Cão in 1485 and Bartolomeu Dias in 1486, like most of interior Sub-Saharan Africa, Namibia was not extensively explored by Europeans until the 19th century
33.
Nigeria
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Its coast in the south lies on the Gulf of Guinea in the Atlantic Ocean. It comprises 36 states and the Federal Capital Territory, where the capital, Nigeria is officially a democratic secular country. Modern-day Nigeria has been the site of numerous kingdoms and tribal states over the millennia, the modern state originated from British colonial rule beginning in the 19th century, and the merging of the Southern Nigeria Protectorate and Northern Nigeria Protectorate in 1914. The British set up administrative and legal structures whilst practising indirect rule through traditional chiefdoms, Nigeria became a formally independent federation in 1960, and plunged into a civil war from 1967 to 1970. Nigeria is often referred to as the Giant of Africa, owing to its large population, with approximately 184 million inhabitants, Nigeria is the most populous country in Africa and the seventh most populous country in the world. Nigeria has one of the largest populations of youth in the world, Nigeria is divided roughly in half between Christians, who live mostly in the southern part of the country, and Muslims in the northern part. A minority of the population practise religions indigenous to Nigeria, such as native to the Igbo. As of 2015, Nigeria is the worlds 20th largest economy, worth more than $500 billion and $1 trillion in terms of nominal GDP and it overtook South Africa to become Africas largest economy in 2014. The 2013 debt-to-GDP ratio was 11 percent, Nigeria is a member of the MINT group of countries, which are widely seen as the globes next BRIC-like economies. It is also listed among the Next Eleven economies set to become among the biggest in the world, Nigeria is a founding member of the African Union and a member of many other international organizations, including the United Nations, the Commonwealth of Nations and OPEC. The name Nigeria was taken from the Niger River running through the country and this name was coined in the late 19th century by British journalist Flora Shaw, who later married Lord Lugard, a British colonial administrator. The origin of the name Niger, which applied only to the middle reaches of the Niger River, is uncertain. The word is likely an alteration of the Tuareg name egerew n-igerewen used by inhabitants along the middle reaches of the river around Timbuktu prior to 19th-century European colonialism. The Nok civilisation of Northern Nigeria flourished between 500 BC and AD200, producing life-sized terracotta figures which are some of the earliest known sculptures in Sub-Saharan Africa, further north, the cities Kano and Katsina have a recorded history dating to around 999 AD. Hausa kingdoms and the Kanem-Bornu Empire prospered as trade posts between North and West Africa, the Kingdom of Nri of the Igbo people consolidated in the 10th century and continued until it lost its sovereignty to the British in 1911. Nri was ruled by the Eze Nri, and the city of Nri is considered to be the foundation of Igbo culture, Nri and Aguleri, where the Igbo creation myth originates, are in the territory of the Umeuri clan. Members of the clan trace their lineages back to the patriarchal king-figure Eri, in West Africa, the oldest bronzes made using the lost-wax process were from Igbo Ukwu, a city under Nri influence. The Yoruba kingdoms of Ife and Oyo in southwestern Nigeria became prominent in the 12th and 14th centuries, the oldest signs of human settlement at Ifes current site date back to the 9th century, and its material culture includes terracotta and bronze figures
34.
United States
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Forty-eight of the fifty states and the federal district are contiguous and located in North America between Canada and Mexico. The state of Alaska is in the northwest corner of North America, bordered by Canada to the east, the state of Hawaii is an archipelago in the mid-Pacific Ocean. The U. S. territories are scattered about the Pacific Ocean, the geography, climate and wildlife of the country are extremely diverse. At 3.8 million square miles and with over 324 million people, the United States is the worlds third- or fourth-largest country by area, third-largest by land area. It is one of the worlds most ethnically diverse and multicultural nations, paleo-Indians migrated from Asia to the North American mainland at least 15,000 years ago. European colonization began in the 16th century, the United States emerged from 13 British colonies along the East Coast. Numerous disputes between Great Britain and the following the Seven Years War led to the American Revolution. On July 4,1776, during the course of the American Revolutionary War, the war ended in 1783 with recognition of the independence of the United States by Great Britain, representing the first successful war of independence against a European power. The current constitution was adopted in 1788, after the Articles of Confederation, the first ten amendments, collectively named the Bill of Rights, were ratified in 1791 and designed to guarantee many fundamental civil liberties. During the second half of the 19th century, the American Civil War led to the end of slavery in the country. By the end of century, the United States extended into the Pacific Ocean. The Spanish–American War and World War I confirmed the status as a global military power. The end of the Cold War and the dissolution of the Soviet Union in 1991 left the United States as the sole superpower. The U. S. is a member of the United Nations, World Bank, International Monetary Fund, Organization of American States. The United States is a developed country, with the worlds largest economy by nominal GDP. It ranks highly in several measures of performance, including average wage, human development, per capita GDP. While the U. S. economy is considered post-industrial, characterized by the dominance of services and knowledge economy, the United States is a prominent political and cultural force internationally, and a leader in scientific research and technological innovations. In 1507, the German cartographer Martin Waldseemüller produced a map on which he named the lands of the Western Hemisphere America after the Italian explorer and cartographer Amerigo Vespucci
35.
California
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California is the most populous state in the United States and the third most extensive by area. Located on the western coast of the U. S, California is bordered by the other U. S. states of Oregon, Nevada, and Arizona and shares an international border with the Mexican state of Baja California. Los Angeles is Californias most populous city, and the second largest after New York City. The Los Angeles Area and the San Francisco Bay Area are the nations second- and fifth-most populous urban regions, California also has the nations most populous county, Los Angeles County, and its largest county by area, San Bernardino County. The Central Valley, an agricultural area, dominates the states center. What is now California was first settled by various Native American tribes before being explored by a number of European expeditions during the 16th and 17th centuries, the Spanish Empire then claimed it as part of Alta California in their New Spain colony. The area became a part of Mexico in 1821 following its war for independence. The western portion of Alta California then was organized as the State of California, the California Gold Rush starting in 1848 led to dramatic social and demographic changes, with large-scale emigration from the east and abroad with an accompanying economic boom. If it were a country, California would be the 6th largest economy in the world, fifty-eight percent of the states economy is centered on finance, government, real estate services, technology, and professional, scientific and technical business services. Although it accounts for only 1.5 percent of the states economy, the story of Calafia is recorded in a 1510 work The Adventures of Esplandián, written as a sequel to Amadis de Gaula by Spanish adventure writer Garci Rodríguez de Montalvo. The kingdom of Queen Calafia, according to Montalvo, was said to be a land inhabited by griffins and other strange beasts. This conventional wisdom that California was an island, with maps drawn to reflect this belief, shortened forms of the states name include CA, Cal. Calif. and US-CA. Settled by successive waves of arrivals during the last 10,000 years, various estimates of the native population range from 100,000 to 300,000. The Indigenous peoples of California included more than 70 distinct groups of Native Americans, ranging from large, settled populations living on the coast to groups in the interior. California groups also were diverse in their organization with bands, tribes, villages. Trade, intermarriage and military alliances fostered many social and economic relationships among the diverse groups, the first European effort to explore the coast as far north as the Russian River was a Spanish sailing expedition, led by Portuguese captain Juan Rodríguez Cabrillo, in 1542. Some 37 years later English explorer Francis Drake also explored and claimed a portion of the California coast in 1579. Spanish traders made unintended visits with the Manila galleons on their trips from the Philippines beginning in 1565
36.
Colorado
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Colorado is a state in the United States encompassing most of the Southern Rocky Mountains as well as the northeastern portion of the Colorado Plateau and the western edge of the Great Plains. Colorado is part of the Western United States, the Southwestern United States, Colorado is the 8th most extensive and the 21st most populous of the 50 United States. The United States Census Bureau estimates that the population of Colorado was 5,540,545 on July 1,2016, the state was named for the Colorado River, which Spanish travelers named the Río Colorado for the ruddy silt the river carried from the mountains. The Territory of Colorado was organized on February 28,1861, Colorado is nicknamed the Centennial State because it became a state in the same year as the centennial of the United States Declaration of Independence. Colorado is noted for its landscape of mountains, forests, high plains, mesas, canyons, plateaus, rivers. Denver is the capital and the most populous city of Colorado, residents of the state are properly known as Coloradans, although the term Coloradoan has been used archaically and lives on in the title of Fort Collins newspaper, the Coloradoan. Colorado, Wyoming and Utah are the states which have boundaries defined solely by lines of latitude and longitude. The summit of Mount Elbert at 14,440 feet elevation in Lake County is the highest point in Colorado, Colorado is the only U. S. state that lies entirely above 1,000 meters elevation. The point where the Arikaree River flows out of Yuma County, Colorado and this point, which holds the distinction of being the highest low elevation point of any state, is higher than the high elevation points of 18 states and the District of Columbia. A little less than one half of the area of Colorado is flat, East of the Rocky Mountains are the Colorado Eastern Plains of the High Plains, the section of the Great Plains within Nebraska at elevations ranging from roughly 3,350 to 7,500 feet. The Colorado plains were mostly prairies, but they have many patches of forests, buttes. Eastern Colorado is presently covered in farmland and rangeland, along with small farming villages. Precipitation is fair, averaging from 15 to 25 inches annually, corn, wheat, hay, soybeans, and oats are all typical crops, and most of the villages and towns in this region boast both a water tower and a grain elevator. Irrigation water is available from the South Platte, the Arkansas River, and a few other streams, however, heavy use of ground water from wells for irrigation has caused underground water reserves to decline. As well as agriculture, eastern Colorado hosts considerable livestock, such as cattle ranches. Roughly 70% of Colorados population resides along the edge of the Rocky Mountains in the Front Range Urban Corridor between Cheyenne, Wyoming, and Pueblo, Colorado. This region is protected from prevailing storms that blow in from the Pacific Ocean region by the high Rockies in the middle of Colorado. The Front Range includes Denver, Boulder, Fort Collins, Loveland, Colorado Springs, Pueblo, Greeley and other townships, on the other side of the Rockies, the significant population centers in Western Colorado are the cities of Grand Junction, Durango, and Montrose
37.
Maine
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Maine is the northernmost state in the New England region of the northeastern United States. Maine is the 39th most extensive and the 41st most populous of the U. S. states and territories and it is bordered by New Hampshire to the west, the Atlantic Ocean to the east, and the Canadian provinces of New Brunswick and Quebec to the north. Maine is the easternmost state in the contiguous United States, and it is known for its jagged, rocky coastline, low, rolling mountains, heavily forested interior, and picturesque waterways, and also its seafood cuisine, especially clams and lobster. There is a continental climate throughout the state, even in areas such as its most populous city of Portland. For thousands of years, indigenous peoples were the inhabitants of the territory that is now Maine. At the time of European arrival in what is now Maine, the first European settlement in the area was by the French in 1604 on Saint Croix Island, by Pierre Dugua, Sieur de Mons. The first English settlement was the short-lived Popham Colony, established by the Plymouth Company in 1607, as Maine entered the 18th century, only a half dozen European settlements had survived. Loyalist and Patriot forces contended for Maines territory during the American Revolution, Maine was part of the Commonwealth of Massachusetts until 1820, when it voted to secede from Massachusetts to become an independent state. On March 15,1820, it was admitted to the Union as the 23rd state under the Missouri Compromise, there is no definitive explanation for the origin of the name Maine, but the most likely origin is the name given by early explorers after a province in France. Whatever the origin, the name was fixed for English settlers in 1665 when the English Kings Commissioners ordered that the Province of Maine be entered from then on in official records. The state legislature in 2001 adopted a resolution establishing Franco-American Day, other theories mention earlier places with similar names, or claim it is a nautical reference to the mainland. Attempts to uncover the history of the name of Maine began with James Sullivans 1795 History of the District of Maine. He made the allegation that the Province of Maine was a compliment to the queen of Charles I, Henrietta Maria. MAINE appears in the Domesday Book of 1086 in reference to the county of Dorset, the view generally held among British place name scholars is that Mayne in Dorset is Brythonic, corresponding to modern Welsh maen, plural main or meini. Some early spellings are, MAINE1086, MEINE1200, MEINES1204, mason had served with the Royal Navy in the Orkney Islands where the chief island is called Mainland, a possible name derivation for these English sailors. Initially, several tracts along the coast of New England were referred to as Main or Maine, Maine is the only state whose name has exactly one syllable. The original inhabitants of the territory that is now Maine were Algonquian-speaking Wabanaki peoples, including the Abenaki, Passamaquoddy, Maliseet and Penobscot, who had a loose confederacy. European contact with what is now called Maine started around 1200 CE when Norwegians interacted with the native Penobscot in present-day Hancock County, most likely through trade
38.
Virginia
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Virginia is a state located in the Mid-Atlantic region of the United States, as well as in the historic Southeast. The geography and climate of the Commonwealth are shaped by the Blue Ridge Mountains and the Chesapeake Bay, the capital of the Commonwealth is Richmond, Virginia Beach is the most populous city, and Fairfax County is the most populous political subdivision. The Commonwealths estimated population as of 2014 is over 8.3 million, the areas history begins with several indigenous groups, including the Powhatan. In 1607 the London Company established the Colony of Virginia as the first permanent New World English colony, slave labor and the land acquired from displaced Native American tribes each played a significant role in the colonys early politics and plantation economy. Although the Commonwealth was under one-party rule for nearly a century following Reconstruction, the Virginia General Assembly is the oldest continuous law-making body in the New World. The state government was ranked most effective by the Pew Center on the States in both 2005 and 2008 and it is unique in how it treats cities and counties equally, manages local roads, and prohibits its governors from serving consecutive terms. Virginias economy changed from agricultural to industrial during the 1960s and 1970s. Virginia has an area of 42,774.2 square miles, including 3,180.13 square miles of water. Virginias boundary with Maryland and Washington, D. C. extends to the mark of the south shore of the Potomac River. The southern border is defined as the 36° 30′ parallel north, the border with Tennessee was not settled until 1893, when their dispute was brought to the U. S. Supreme Court. The Chesapeake Bay separates the portion of the Commonwealth from the two-county peninsula of Virginias Eastern Shore. The bay was formed from the river valleys of the Susquehanna River. Many of Virginias rivers flow into the Chesapeake Bay, including the Potomac, Rappahannock, York, and James, the Tidewater is a coastal plain between the Atlantic coast and the fall line. It includes the Eastern Shore and major estuaries of Chesapeake Bay, the Piedmont is a series of sedimentary and igneous rock-based foothills east of the mountains which were formed in the Mesozoic era. The region, known for its clay soil, includes the Southwest Mountains around Charlottesville. The Blue Ridge Mountains are a province of the Appalachian Mountains with the highest points in the state. The Ridge and Valley region is west of the mountains and includes the Great Appalachian Valley, the region is carbonate rock based and includes Massanutten Mountain. The Cumberland Plateau and the Cumberland Mountains are in the southwest corner of Virginia, in this region, rivers flow northwest, with a dendritic drainage system, into the Ohio River basin
39.
Zimbabwe
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Zimbabwe, officially the Republic of Zimbabwe, is a landlocked country located in southern Africa, between the Zambezi and Limpopo Rivers. It is bordered by South Africa to the south, Botswana to the west and southwest, Zambia to the northwest, although it does not border Namibia, less than 200 metres of the Zambezi River separates it from that country. The capital and largest city is Harare, a country of roughly 13 million people, Zimbabwe has 16 official languages, with English, Shona, and Ndebele the most commonly used. Since the 11th century, present-day Zimbabwe has been the site of several organised states and kingdoms as well as a route for migration. The British South Africa Company of Cecil Rhodes first demarcated the present territory during the 1890s, in 1965, the conservative white minority government unilaterally declared independence as Rhodesia. Zimbabwe then rejoined the Commonwealth of Nations—which it withdrew from in 2003 and it is a member of the United Nations, the Southern African Development Community, the African Union, and the Common Market for Eastern and Southern Africa. Robert Mugabe became Prime Minister of Zimbabwe in 1980, when his ZANU-PF party won the following the end of white minority rule. Under Mugabes authoritarian regime, the security apparatus has dominated the country. Mugabe has maintained the revolutionary socialist rhetoric from the Cold War era, the name Zimbabwe stems from a Shona term for Great Zimbabwe, an ancient ruined city in the countrys south-east whose remains are now a protected site. Two different theories address the origin of the word, many sources hold that Zimbabwe derives from dzimba-dza-mabwe, translated from the Karanga dialect of Shona as large houses of stone. The Karanga-speaking Shona people live around Great Zimbabwe in the province of Masvingo. Zimbabwe was formerly known as Southern Rhodesia, Rhodesia, and Zimbabwe Rhodesia, a further alternative, put forward by nationalists in Matabeleland, had been Matopos, referring to the Matopos Hills to the south of Bulawayo. In a 2001 interview, black nationalist Edson Zvobgo recalled that Mawema mentioned the name during a rally, and it caught hold. The black nationalist factions subsequently used the name the during the Second Chimurenga campaigns against the Rhodesian government during the Rhodesian Bush War of 1964-1979, major factions in this camp included the Zimbabwe African National Union, and the Zimbabwe African Peoples Union. Proto-Shona-speaking societies first emerged in the middle Limpopo valley in the 9th century before moving on to the Zimbabwean highlands, the Zimbabwean plateau eventually became the centre of subsequent Shona states, beginning around the 10th century. Around the early 10th century, trade developed with Arab merchants on the Indian Ocean coast, the main archaeological site uses a unique dry stone architecture. The Kingdom of Mapungubwe was the first in a series of sophisticated trade states developed in Zimbabwe by the time of the first European explorers from Portugal and they traded in gold, ivory, and copper for cloth and glass. From about 1300 until 1600, Mapungubwe was eclipsed by the Kingdom of Zimbabwe and this Shona state further refined and expanded upon Mapungubwes stone architecture, which survives to this day at the ruins of the kingdoms capital of Great Zimbabwe
40.
Environmental issue
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Environmental issues are harmful effects of human activity on the biophysical environment. Environmental protection is a practice of protecting the environment on individual, organizational or governmental levels. Environmentalism, a social and environmental movement, addresses environmental issues through advocacy, education, the carbon dioxide equivalent of greenhouse gases in the atmosphere has already exceeded 400 parts per million. This level is considered a tipping point, the amount of greenhouse gas in the atmosphere is already above the threshold that can potentially cause dangerous climate change. We are already at risk of many areas of pollution. Its not next year or next decade, its now. Report from the UN Office for the Coordination of Humanitarian Affairs, Environment destruction caused by humans is a problem. By year 2050, the human population is expected to grow by 2 billion people. The human effects on Earth can be seen in different ways. A main one is the rise, and according to the report ”Our Changing Climate”. Since 1895, the U. S. average temperature has increased from 1.3 °F to 1.9 °F, major current environmental issues may include climate change, pollution, environmental degradation, and resource depletion etc. The conservation movement lobbies for protection of endangered species and protection of any ecologically valuable areas, genetically modified foods. The level of understanding of Earth has increased markebly in recent times through science especially with the application of the scientific method, environmental science is now a multi-disciplinary academic study taught and researched at many universities. This is used as a basis for addressing environmental issues, large amounts of data have been gathered and these are collated into reports, of which a common type is the State of the Environment publications. Environmental issues are addressed at a regional, national or international level by government organizations, the largest international agency, set up in 1972, is the United Nations Environment Programme. International non-governmental organizations include Greenpeace, Friends of the Earth and World Wide Fund for Nature, governments enact environmental policy and enforce environmental law and this is done to differing degrees around the world. Sustainability is the key to prevent or reduce the effect of environmental issues, for humans to live sustainably, the Earths natural resources must be used at a rate at which they can be replenished. Concerns for the environment have prompted the formation of green parties, initially these were formed in Australia, New Zealand and Germany but are now present in many other countries. There are a number of films being produced on environmental issues, especially on climate change
41.
Democratic Republic of Congo
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The Democratic Republic of the Congo, also known as DR Congo, DRC, DROC, East Congo, Congo-Kinshasa, or simply the Congo is a country located in Central Africa. From 1971 to 1997 it was named, and is still called, Zaire. It is the second-largest country in Africa by area and eleventh largest in the world, the Congolese Civil Wars, which began in 1996, brought about the end of Mobutu Sese Sekos 32-year reign and devastated the country. These wars ultimately involved nine African nations, multiple groups of UN peacekeepers and twenty armed groups, besides the capital, Kinshasa, the other major cities, Lubumbashi and Mbuji-Mayi, are both mining communities. DR Congos largest export is raw minerals, with China accepting over 50% of DRCs exports in 2012, as of 2015, according to the Human Development Index, DR Congo has a low level of human development, ranking 176 out of 187 countries. The country was known officially as the Democratic Republic of the Congo from 1965 to 27 October 1971, in 1992, the Sovereign National Conference voted to change the name of the country to the Democratic Republic of the Congo, but the change was not put into practice. The countrys name was restored by former president Laurent-Désiré Kabila following the fall of longtime dictator Mobutu Sese Seko in 1997, some historians think that Bantu peoples began settling in the extreme northwest of Central Africa at the beginning of the 5th century and then gradually started to expand southward. Their propagation was accelerated by the transition from Stone Age to Iron Age techniques, the people living in the south and southwest were mostly San Bushmen and hunter-gatherer groups, whose technology involved only minimal use of metal technologies. The development of tools during this time period revolutionized agriculture. This led to the displacement of the groups in the east and southeast. The 10th century marked the expansion of the Bantu in West-Central Africa. Rising populations soon made intricate local, regional and foreign commercial networks that traded mostly in salt, iron. Belgian exploration and administration took place from the 1870s until the 1920s and it was first led by Sir Henry Morton Stanley, who undertook his explorations under the sponsorship of King Leopold II of Belgium. The eastern regions of the precolonial Congo were heavily disrupted by constant slave raiding, mainly from Arab–Swahili slave traders such as the infamous Tippu Tip, Leopold had designs on what was to become the Congo as a colony. Leopold formally acquired rights to the Congo territory at the Conference of Berlin in 1885 and he named it the Congo Free State. Leopolds rėgime began various infrastructure projects, such as construction of the railway ran from the coast to the capital of Leopoldville. Nearly all such projects were aimed at making it easier to increase the assets which Leopold. In the Free State, colonists brutalized the local population into producing rubber, for which the spread of automobiles, rubber sales made a fortune for Leopold, who built several buildings in Brussels and Ostend to honor himself and his country
42.
Coltan mining and ethics
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Coltan is a metallic ore from which the very similar elements niobium, also known as columbium, and tantalum are extracted. Coltan mining specifically in the Democratic Republic of Congo has been associated with human rights violations, the coltan industry is worth billions of dollars per year. Prices for coltan range between $50 and $200 per pound- and has undergone a series of radical location shifts since its inception. In 2006, Australia, Brazil, and Canada produced 80% of the world’s coltan, as of 2012, coltan’s main producers are Australia, Brazil, Canada, Mozambique, and Democratic Republic of Congo via Rwanda, countries that produce about 66% of the world’s coltan. Additional coltan reserves have been all over the world on every continent except Antarctica. It is believed that sufficient reserves exist in developed countries, but for a variety of reasons, currently, coltan products are sold in private, unregulated markets, unlike metals such as gold, copper, zinc, and tin. This means that there are no standards for mining operations and any safety procedures must come from the owners or their home countries. The United Nations has taken a role in assessing the state of the world’s coltan industry and has cited numerous countries with ethical violations in relationship to coltan mining. Due to the nature of the mining and the number of ore deposits in conflict zones and third-world countries, while the situation in each coltan-producing country is different, there are some notable similarities in the countries whose practices come under fire. The first is the exploitation of workers, particularly child workers. While coltan miners are often paid well, they do not earn a living wage. According to the UN, the right to choice of employment, however, because of the violence in many of the world’s conflict-producing regions, there is little choice in who becomes a coltan miner despite what people want. In Africa, mines are connected in some way to militia groups, while in South America. Many of the burgeoning coltan producers are resource-rich developing countries with economies that are largely dependent on mining non-renewable resources. This indicates a danger attached to even clean coltan operations in developing countries, groups that study developing nations such as Oxfam caution against a developing country putting much of its capital into mining operations, especially single mineral developments. This land tension typically leads to economic performance and political instability. In addition to the rights issues attached to the coltan industry. Coltan, like any metal, is a toxic contaminant, since it is usually pan-mined, the mining process and slurry from this process contaminates the water supply and is harmful to the entire ecosystem
43.
Wayback Machine
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The Internet Archive launched the Wayback Machine in October 2001. It was set up by Brewster Kahle and Bruce Gilliat, and is maintained with content from Alexa Internet, the service enables users to see archived versions of web pages across time, which the archive calls a three dimensional index. Since 1996, the Wayback Machine has been archiving cached pages of websites onto its large cluster of Linux nodes and it revisits sites every few weeks or months and archives a new version. Sites can also be captured on the fly by visitors who enter the sites URL into a search box, the intent is to capture and archive content that otherwise would be lost whenever a site is changed or closed down. The overall vision of the machines creators is to archive the entire Internet, the name Wayback Machine was chosen as a reference to the WABAC machine, a time-traveling device used by the characters Mr. Peabody and Sherman in The Rocky and Bullwinkle Show, an animated cartoon. These crawlers also respect the robots exclusion standard for websites whose owners opt for them not to appear in search results or be cached, to overcome inconsistencies in partially cached websites, Archive-It. Information had been kept on digital tape for five years, with Kahle occasionally allowing researchers, when the archive reached its fifth anniversary, it was unveiled and opened to the public in a ceremony at the University of California, Berkeley. Snapshots usually become more than six months after they are archived or, in some cases, even later. The frequency of snapshots is variable, so not all tracked website updates are recorded, Sometimes there are intervals of several weeks or years between snapshots. After August 2008 sites had to be listed on the Open Directory in order to be included. As of 2009, the Wayback Machine contained approximately three petabytes of data and was growing at a rate of 100 terabytes each month, the growth rate reported in 2003 was 12 terabytes/month, the data is stored on PetaBox rack systems manufactured by Capricorn Technologies. In 2009, the Internet Archive migrated its customized storage architecture to Sun Open Storage, in 2011 a new, improved version of the Wayback Machine, with an updated interface and fresher index of archived content, was made available for public testing. The index driving the classic Wayback Machine only has a bit of material past 2008. In January 2013, the company announced a ground-breaking milestone of 240 billion URLs, in October 2013, the company announced the Save a Page feature which allows any Internet user to archive the contents of a URL. This became a threat of abuse by the service for hosting malicious binaries, as of December 2014, the Wayback Machine contained almost nine petabytes of data and was growing at a rate of about 20 terabytes each week. Between October 2013 and March 2015 the websites global Alexa rank changed from 162 to 208, in a 2009 case, Netbula, LLC v. Chordiant Software Inc. defendant Chordiant filed a motion to compel Netbula to disable the robots. Netbula objected to the motion on the ground that defendants were asking to alter Netbulas website, in an October 2004 case, Telewizja Polska USA, Inc. v. Echostar Satellite, No.02 C3293,65 Fed. 673, a litigant attempted to use the Wayback Machine archives as a source of admissible evidence, Telewizja Polska is the provider of TVP Polonia and EchoStar operates the Dish Network
44.
Borate minerals
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The borate minerals are minerals which contain a borate anion group. The borate units may be polymerised similar to the SiO4 unit of the silicate mineral class and this results in B2O5, B3O6, B2O4 anions as well as more complex structures which include hydroxide or halogen anions. Many borate minerals, such as borax, colemanite, and ulexite, are salts, soft, readily soluble, however, some, such as boracite, are hard and resistant to weathering, more similar to the silicates. There are over 100 different borate minerals, borate minerals include, Kernite Na2B4O63·3H2O Borax Na2B4O54·8H2O Ulexite NaCaB5O66·5H2O Colemanite CaB3O43·H2O Boracite Mg3B7O13Cl IMA-CNMNC proposes a new hierarchical scheme. This list uses it to modify the Classification of Nickel–Strunz
45.
Sussexite
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Sussexite is a manganese borate mineral MnBO2. Crystals are monoclinic prismatic and typically fibrous in occurrence, colour is white, pink, yellowish white with a pearly lustre. It has a Mohs hardness of 3 and a gravity of 3.12. It is named after the Franklin Mining District in Sussex County, New Jersey, sussexite also occurs in France, Italy, Namibia, North Korea, South Africa, Switzerland, and the US states of Michigan, New Jersey, Utah and Virginia
46.
Carbonate minerals
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IMA-CNMNC proposes a new hierarchical scheme. This list uses the Classification of Nickel–Strunz
