1.
Phyllosilicates
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Silicate minerals are rock-forming minerals made up of silicate groups. They are the largest and most important class of rock-forming minerals and they are classified based on the structure of their silicate groups, which contain different ratios of silicon and oxygen. Nesosilicates, or orthosilicates, have the orthosilicate ion, which constitute isolated 4− tetrahedra that are connected only by interstitial cations and these exist as 3-member 6− and 6-member 12− rings, where T stands for a tetrahedrally coordinated cation. Inosilicates, or chain silicates, have interlocking chains of silicate tetrahedra with either SiO3,1,3 ratio, for single chains or Si4O11,4,11 ratio, for double chains. Nickel–Strunz classification,09. D Pyroxene group Enstatite – orthoferrosilite series Enstatite – MgSiO3 Ferrosilite – FeSiO3 Pigeonite – Ca0.251, all phyllosilicate minerals are hydrated, with either water or hydroxyl groups attached. Serpentine subgroup Antigorite – Mg3Si2O54 Chrysotile – Mg3Si2O54 Lizardite – Mg3Si2O54 Clay minerals group Halloysite – Al2Si2O54 Kaolinite – Al2Si2O54 Illite – 24O10 Montmorillonite –0 and this group comprises nearly 75% of the crust of the Earth. Tectosilicates, with the exception of the group, are aluminosilicates. Nickel–Strunz classification,09. F and 09. G,04. A, an introduction to the rock-forming minerals. Wise, W. S. Zussman, J. Rock-forming minerals, P.982 pp. Hurlbut, Cornelius S. Danas Manual of Mineralogy. Mindat. org, Dana classification Webmineral, Danas New Silicate Classification Media related to Silicates at Wikimedia Commons
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.
Lepidolite
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Lepidolite is a lilac-gray or rose-colored member of the mica group of minerals with formula K24O102. It is the most abundant lithium-bearing mineral and is a source of this metal. It is a mineral and a member of the polylithionite-trilithionite series. It is associated with other lithium-bearing minerals like spodumene in pegmatite bodies and it is one of the major sources of the rare alkali metals rubidium and caesium. In 1861 Robert Bunsen and Gustav Kirchhoff extracted 150 kg of lepidolite and yielded a few grams of rubidium salts for analysis and it occurs in granite pegmatites, in some high-temperature quartz veins, greisens and granites. Associated minerals include quartz, feldspar, spodumene, amblygonite, tourmaline, columbite, cassiterite, topaz, notable occurrences include Brazil, Ural Mountains, Russia, California, United States, Tanco Mine, Bernic Lake, Manitoba, Canada, and Madagascar
4.
Biotite
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Biotite is a common phyllosilicate mineral within the mica group, with the approximate chemical formula K 3AlSi 3O102. Hausmann in 1847 in honor of the French physicist Jean-Baptiste Biot, iron, magnesium, aluminium, silicon, oxygen, and hydrogen form sheets that are weakly bound together by potassium ions. It is sometimes called iron mica because it is more iron-rich than phlogopite and it is also sometimes called black mica as opposed to white mica – both form in some rocks, and in some instances side-by-side. Like other mica minerals, biotite has a perfect basal cleavage, and consists of flexible sheets, or lamellae. It has a crystal system, with tabular to prismatic crystals with an obvious pinacoid termination. It has four faces and two pinacoid faces to form a pseudohexagonal crystal. Although not easily seen because of the cleavage and sheets, fracture is uneven and it appears greenish to brown or black, and even yellow when weathered. It can be transparent to opaque, has a vitreous to pearly luster, when biotite is found in large chunks, they are called “books” because it resembles a book with pages of many sheets. The color of biotite is usually black and the mineral has a hardness of 2. 5-3 on the Mohs scale of mineral hardness, biotite dissolves in both acid and alkaline aqueous solutions, with the highest dissolution rates at low pH. However, biotite dissolution is highly anisotropic with crystal edge surfaces reacting 45 to 132 times faster than basal surfaces, under cross-polarized light biotite can generally be identified by the gnarled birds eye extinction. Biotite is found in a variety of igneous and metamorphic rocks. For instance, biotite occurs in the lava of Mount Vesuvius, biotite in granite tends to be poorer in magnesium than the biotite found in its volcanic equivalent, rhyolite. Biotite is an essential phenocryst in some varieties of lamprophyre, biotite is occasionally found in large cleavable crystals, especially in pegmatite veins, as in New England, Virginia and North Carolina. Other notable occurrences include Bancroft and Sudbury, Ontario and it is an essential constituent of many metamorphic schists, and it forms in suitable compositions over a wide range of pressure and temperature. It has been estimated that biotite comprises up to 7% of the continental crust. The largest documented single crystals of biotite were approximately 7 m2 sheets found in Iveland, biotite is used extensively to constrain ages of rocks, by either potassium-argon dating or argon-argon dating. Because argon escapes readily from the crystal structure at high temperatures. Biotite is also useful in assessing temperature histories of metamorphic rocks, because the partitioning of iron and magnesium between biotite and garnet is sensitive to temperature
5.
Phlogopite
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Phlogopite is a yellow, greenish, or reddish-brown member of the mica family of phyllosilicates. It is also known as magnesium mica, phlogopite is the magnesium endmember of the biotite solid solution series, with the chemical formula KMg3AlSi3O102. Iron substitutes for magnesium in variable amounts leading to the more common biotite with higher iron content, for physical and optical identification, it shares most of the characteristic properties of biotite. Phlogopite is an important and relatively common end-member composition of biotite, several igneous associations are noted, high-alumina basalts, ultrapotassic igneous rocks, and ultramafic rocks. The basaltic occurrence of phlogopite is in association with picrite basalts, phlogopite is stable in basaltic compositions at high pressures and is often present as partially resorbed phenocrysts or an accessory phase in basalts generated at depth. Phlogopite in this association is a primary igneous mineral present because of the depth of melting, phlogopite is often found in association with ultramafic intrusions as a secondary alteration phase within metasomatic margins of large layered intrusions. In some cases the phlogopite is considered to be produced by autogenic alteration during cooling, in other instances, metasomatism has resulted in phlogopite formation within large volumes, as in the ultramafic massif at Finero, Italy, within the Ivrea zone. Phlogopite is encountered as a primary igneous phenocryst within lamproites and lamprophyres, the largest documented single crystal of phlogopite was found in Lacey mine, Ontario, Canada, it measured 10x4. 3x4.3 m3 and weighed about 330 tonnes. Similar-sized crystals were found in Karelia, Russia. Howie, and J. Zussman, Rock-forming minerals, v.3, sheet silicates, p. 42–54 Spencer, Leonard James
6.
Muscovite
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Muscovite is a hydrated phyllosilicate mineral of aluminium and potassium with formula KAl22, or 236. It has a perfect basal cleavage yielding remarkably thin laminae which are often highly elastic. Sheets of muscovite 5 m ×3 m have been found in Nellore, Muscovite has a Mohs hardness of 2–2.25 parallel to the face,4 perpendicular to the and a specific gravity of 2. 76–3. It can be colorless or tinted through grays, browns, greens, yellows, or violet or red and it is anisotropic and has high birefringence. The green, chromium-rich variety is called fuchsite, mariposite is also a type of muscovite. In pegmatites, it is found in immense sheets that are commercially valuable. Muscovite is in demand for the manufacture of fireproofing and insulating materials, the name muscovite comes from Muscovy-glass, a name given to the mineral in Elizabethan England due to its use in medieval Russia as a cheaper alternative to glass in windows. Media related to Muscovite at Wikimedia Commons
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.
Melting point
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The melting point of a solid is the temperature at which it changes state from solid to liquid at atmospheric pressure. At the melting point the solid and liquid phase exist in equilibrium, the melting point of a substance depends on pressure and is usually specified at standard pressure. When considered as the temperature of the change from liquid to solid. Because of the ability of some substances to supercool, the point is not considered as a characteristic property of a substance. For most substances, melting and freezing points are approximately equal, for example, the melting point and freezing point of mercury is 234.32 kelvins. However, certain substances possess differing solid-liquid transition temperatures, for example, agar melts at 85 °C and solidifies from 31 °C to 40 °C, such direction dependence is known as hysteresis. The melting point of ice at 1 atmosphere of pressure is close to 0 °C. In the presence of nucleating substances the freezing point of water is the same as the melting point, the chemical element with the highest melting point is tungsten, at 3687 K, this property makes tungsten excellent for use as filaments in light bulbs. Many laboratory techniques exist for the determination of melting points, a Kofler bench is a metal strip with a temperature gradient. Any substance can be placed on a section of the strip revealing its thermal behaviour at the temperature at that point, differential scanning calorimetry gives information on melting point together with its enthalpy of fusion. A basic melting point apparatus for the analysis of crystalline solids consists of an oil bath with a transparent window, the several grains of a solid are placed in a thin glass tube and partially immersed in the oil bath. The oil bath is heated and with the aid of the melting of the individual crystals at a certain temperature can be observed. In large/small devices, the sample is placed in a heating block, the measurement can also be made continuously with an operating process. For instance, oil refineries measure the point of diesel fuel online, meaning that the sample is taken from the process. This allows for more frequent measurements as the sample does not have to be manually collected, for refractory materials the extremely high melting point may be determined by heating the material in a black body furnace and measuring the black-body temperature with an optical pyrometer. For the highest melting materials, this may require extrapolation by several hundred degrees, the spectral radiance from an incandescent body is known to be a function of its temperature. An optical pyrometer matches the radiance of a body under study to the radiance of a source that has been previously calibrated as a function of temperature, in this way, the measurement of the absolute magnitude of the intensity of radiation is unnecessary. However, known temperatures must be used to determine the calibration of the pyrometer, for temperatures above the calibration range of the source, an extrapolation technique must be employed
14.
Ontario
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Ontario, one of the 13 provinces and territories of Canada, is located in east-central Canada. It is Canadas most populous province by a margin, accounting for nearly 40 percent of all Canadians. Ontario is fourth-largest in total area when the territories of the Northwest Territories and it is home to the nations capital city, Ottawa, and the nations most populous city, Toronto. There is only about 1 km of land made up of portages including Height of Land Portage on the Minnesota border. Ontario is sometimes divided into two regions, Northern Ontario and Southern Ontario. The great majority of Ontarios population and arable land is located in the south, in contrast, the larger, northern part of Ontario is sparsely populated with cold winters and is heavily forested. The province is named after Lake Ontario, a thought to be derived from Ontarí, io, a Huron word meaning great lake, or possibly skanadario. Ontario has about 250,000 freshwater lakes, the province consists of three main geographical regions, The thinly populated Canadian Shield in the northwestern and central portions, which comprises over half the land area of Ontario. Although this area mostly does not support agriculture, it is rich in minerals and in part covered by the Central and Midwestern Canadian Shield forests, studded with lakes, Northern Ontario is subdivided into two sub-regions, Northwestern Ontario and Northeastern Ontario. The virtually unpopulated Hudson Bay Lowlands in the north and northeast, mainly swampy. Southern Ontario which is further sub-divided into four regions, Central Ontario, Eastern Ontario, Golden Horseshoe, the highest point is Ishpatina Ridge at 693 metres above sea level located in Temagami, Northeastern Ontario. In the south, elevations of over 500 m are surpassed near Collingwood, above the Blue Mountains in the Dundalk Highlands, the Carolinian forest zone covers most of the southwestern region of the province. A well-known geographic feature is Niagara Falls, part of the Niagara Escarpment, the Saint Lawrence Seaway allows navigation to and from the Atlantic Ocean as far inland as Thunder Bay in Northwestern Ontario. Northern Ontario occupies roughly 87 percent of the area of the province. Point Pelee is a peninsula of Lake Erie in southwestern Ontario that is the southernmost extent of Canadas mainland, Pelee Island and Middle Island in Lake Erie extend slightly farther. All are south of 42°N – slightly farther south than the border of California. The climate of Ontario varies by season and location, the effects of these major air masses on temperature and precipitation depend mainly on latitude, proximity to major bodies of water and to a small extent, terrain relief. In general, most of Ontarios climate is classified as humid continental, Ontario has three main climatic regions
15.
Silicate
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A silicate is a compound containing an anionic silicon compound. The great majority of the silicates are oxides, but hexafluorosilicate, orthosilicate is the anion SiO4−4 or its compounds. Related to orthosilicate are families of anions with the formula 2n−, important members are the cyclic and single chain silicates n and the sheet-forming silicates n. Silicates constitute the majority of Earths crust, as well as the terrestrial planets, rocky moons. Sand, Portland cement, and thousands of minerals are examples of silicates, silicate compounds, including the minerals, consist of silicate anions whose charge is balanced by various cations. Myriad silicate anions can exist, and each can form compounds with many different cations, hence this class of compounds is very large. Both minerals and synthetic materials fit in this class, in the vast majority of silicates, including silicate minerals, the Si occupies a tetrahedral environment, being surrounded by 4 oxygen centres. In these structures, the bonds to silicon conform to the octet rule. These tetrahedra sometimes occur as isolated SiO4−4 centres, but most commonly, commonly the silicate anions are chains, double chains, sheets, and three-dimensional frameworks. All these such species have negligible solubility in water at normal conditions, silicates are well characterized as solids, but are less commonly observed in solution. The anion SiO4−4 is the base of silicic acid, Si4. Instead, solutions of silicates are usually observed as mixtures of condensed, the nature of soluble silicates is relevant to understanding biomineralization and the synthesis of aluminosilicates, such as the industrially important catalysts called zeolites. Although the tetrahedron is the coordination geometry for silicon compounds. A well-known example of such a high number is hexafluorosilicate. Octahedral coordination by 6 oxygen centres is observed, at very high pressure, even SiO2 adopts this geometry in the mineral stishovite, a dense polymorph of silica found in the lower mantle of the Earth. This structure is formed by shock during meteorite impacts. In geology and astronomy, the silicate is used to denote types of rock that consist predominantly of silicate minerals. On Earth, a variety of silicate minerals occur in an even wider range of combinations as a result of the processes that form
16.
Silicate minerals
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Silicate minerals are rock-forming minerals made up of silicate groups. They are the largest and most important class of rock-forming minerals and they are classified based on the structure of their silicate groups, which contain different ratios of silicon and oxygen. Nesosilicates, or orthosilicates, have the orthosilicate ion, which constitute isolated 4− tetrahedra that are connected only by interstitial cations and these exist as 3-member 6− and 6-member 12− rings, where T stands for a tetrahedrally coordinated cation. Inosilicates, or chain silicates, have interlocking chains of silicate tetrahedra with either SiO3,1,3 ratio, for single chains or Si4O11,4,11 ratio, for double chains. Nickel–Strunz classification,09. D Pyroxene group Enstatite – orthoferrosilite series Enstatite – MgSiO3 Ferrosilite – FeSiO3 Pigeonite – Ca0.251, all phyllosilicate minerals are hydrated, with either water or hydroxyl groups attached. Serpentine subgroup Antigorite – Mg3Si2O54 Chrysotile – Mg3Si2O54 Lizardite – Mg3Si2O54 Clay minerals group Halloysite – Al2Si2O54 Kaolinite – Al2Si2O54 Illite – 24O10 Montmorillonite –0 and this group comprises nearly 75% of the crust of the Earth. Tectosilicates, with the exception of the group, are aluminosilicates. Nickel–Strunz classification,09. F and 09. G,04. A, an introduction to the rock-forming minerals. Wise, W. S. Zussman, J. Rock-forming minerals, P.982 pp. Hurlbut, Cornelius S. Danas Manual of Mineralogy. Mindat. org, Dana classification Webmineral, Danas New Silicate Classification Media related to Silicates at Wikimedia Commons
17.
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
18.
Monoclinic crystal system
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In crystallography, the monoclinic crystal system is one of the 7 crystal systems. A crystal system is described by three vectors, in the monoclinic system, the crystal is described by vectors of unequal lengths, as in the orthorhombic system. They form a rectangular prism with a parallelogram as its base, hence two vectors are perpendicular, while the third vector meets the other two at an angle other than 90°. There is only one monoclinic Bravais lattice in two dimensions, the oblique lattice, two monoclinic Bravais lattices exist, the primitive monoclinic and the centered monoclinic lattices. In this axis setting, the primitive and base-centered lattices interchange in centering type, sphenoidal is also monoclinic hemimorphic, Domatic is also monoclinic hemihedral, Prismatic is also monoclinic normal. Crystal structure Hurlbut, Cornelius S. Klein, Cornelis, hahn, Theo, ed. International Tables for Crystallography, Volume A, Space Group Symmetry
19.
Crystal
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A crystal or crystalline solid is a solid material whose constituents are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macroscopic single crystals are usually identifiable by their geometrical shape, the scientific study of crystals and crystal formation is known as crystallography. The process of crystal formation via mechanisms of crystal growth is called crystallization or solidification, the word crystal derives from the Ancient Greek word κρύσταλλος, meaning both ice and rock crystal, from κρύος, icy cold, frost. Examples of large crystals include snowflakes, diamonds, and table salt, most inorganic solids are not crystals but polycrystals, i. e. many microscopic crystals fused together into a single solid. Examples of polycrystals include most metals, rocks, ceramics, a third category of solids is amorphous solids, where the atoms have no periodic structure whatsoever. Examples of amorphous solids include glass, wax, and many plastics, Crystals are often used in pseudoscientific practices such as crystal therapy, and, along with gemstones, are sometimes associated with spellwork in Wiccan beliefs and related religious movements. The scientific definition of a crystal is based on the arrangement of atoms inside it. A crystal is a solid where the form a periodic arrangement. For example, when liquid water starts freezing, the change begins with small ice crystals that grow until they fuse. Most macroscopic inorganic solids are polycrystalline, including almost all metals, ceramics, ice, rocks, solids that are neither crystalline nor polycrystalline, such as glass, are called amorphous solids, also called glassy, vitreous, or noncrystalline. These have no periodic order, even microscopically, there are distinct differences between crystalline solids and amorphous solids, most notably, the process of forming a glass does not release the latent heat of fusion, but forming a crystal does. A crystal structure is characterized by its cell, a small imaginary box containing one or more atoms in a specific spatial arrangement. The unit cells are stacked in three-dimensional space to form the crystal, the symmetry of a crystal is constrained by the requirement that the unit cells stack perfectly with no gaps. There are 219 possible crystal symmetries, called space groups. These are grouped into 7 crystal systems, such as cubic crystal system or hexagonal crystal system, Crystals are commonly recognized by their shape, consisting of flat faces with sharp angles. Euhedral crystals are those with obvious, well-formed flat faces, anhedral crystals do not, usually because the crystal is one grain in a polycrystalline solid. The flat faces of a crystal are oriented in a specific way relative to the underlying atomic arrangement of the crystal. This occurs because some surface orientations are more stable than others, as a crystal grows, new atoms attach easily to the rougher and less stable parts of the surface, but less easily to the flat, stable surfaces
20.
Hexagon
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In geometry, a hexagon is a six sided polygon or 6-gon. The total of the angles of any hexagon is 720°. A regular hexagon has Schläfli symbol and can also be constructed as an equilateral triangle, t. A regular hexagon is defined as a hexagon that is both equilateral and equiangular and it is bicentric, meaning that it is both cyclic and tangential. The common length of the sides equals the radius of the circumscribed circle, all internal angles are 120 degrees. A regular hexagon has 6 rotational symmetries and 6 reflection symmetries, the longest diagonals of a regular hexagon, connecting diametrically opposite vertices, are twice the length of one side. Like squares and equilateral triangles, regular hexagons fit together without any gaps to tile the plane, the cells of a beehive honeycomb are hexagonal for this reason and because the shape makes efficient use of space and building materials. The Voronoi diagram of a triangular lattice is the honeycomb tessellation of hexagons. It is not usually considered a triambus, although it is equilateral, the maximal diameter, D is twice the maximal radius or circumradius, R, which equals the side length, t. The minimal diameter or the diameter of the circle, d, is twice the minimal radius or inradius. If a regular hexagon has successive vertices A, B, C, D, E, F, the regular hexagon has Dih6 symmetry, order 12. There are 3 dihedral subgroups, Dih3, Dih2, and Dih1, and 4 cyclic subgroups, Z6, Z3, Z2 and these symmetries express 9 distinct symmetries of a regular hexagon. John Conway labels these by a letter and group order, r12 is full symmetry, and a1 is no symmetry. These two forms are duals of each other and have half the order of the regular hexagon. The i4 forms are regular hexagons flattened or stretched along one symmetry direction and it can be seen as an elongated rhombus, while d2 and p2 can be seen as horizontally and vertically elongated kites. G2 hexagons, with sides parallel are also called hexagonal parallelogons. Each subgroup symmetry allows one or more degrees of freedom for irregular forms, only the g6 subgroup has no degrees of freedom but can seen as directed edges. Hexagons of symmetry g2, i4, and r12, as parallelogons can tessellate the Euclidean plane by translation, other hexagon shapes can tile the plane with different orientations
21.
Atom
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An atom is the smallest constituent unit of ordinary matter that has the properties of a chemical element. Every solid, liquid, gas, and plasma is composed of neutral or ionized atoms, Atoms are very small, typical sizes are around 100 picometers. Atoms are small enough that attempting to predict their behavior using classical physics - as if they were billiard balls, through the development of physics, atomic models have incorporated quantum principles to better explain and predict the behavior. Every atom is composed of a nucleus and one or more bound to the nucleus. The nucleus is made of one or more protons and typically a number of neutrons. Protons and neutrons are called nucleons, more than 99. 94% of an atoms mass is in the nucleus. The protons have an electric charge, the electrons have a negative electric charge. If the number of protons and electrons are equal, that atom is electrically neutral, if an atom has more or fewer electrons than protons, then it has an overall negative or positive charge, respectively, and it is called an ion. The electrons of an atom are attracted to the protons in a nucleus by this electromagnetic force. The number of protons in the nucleus defines to what chemical element the atom belongs, for example, the number of neutrons defines the isotope of the element. The number of influences the magnetic properties of an atom. Atoms can attach to one or more other atoms by chemical bonds to form compounds such as molecules. The ability of atoms to associate and dissociate is responsible for most of the changes observed in nature. The idea that matter is made up of units is a very old idea, appearing in many ancient cultures such as Greece. The word atom was coined by ancient Greek philosophers, however, these ideas were founded in philosophical and theological reasoning rather than evidence and experimentation. As a result, their views on what look like. They also could not convince everybody, so atomism was but one of a number of competing theories on the nature of matter. It was not until the 19th century that the idea was embraced and refined by scientists, in the early 1800s, John Dalton used the concept of atoms to explain why elements always react in ratios of small whole numbers
22.
Latin
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Latin is a classical language belonging to the Italic branch of the Indo-European languages. The Latin alphabet is derived from the Etruscan and Greek alphabets, Latin was originally spoken in Latium, in the Italian Peninsula. Through the power of the Roman Republic, it became the dominant language, Vulgar Latin developed into the Romance languages, such as Italian, Portuguese, Spanish, French, and Romanian. Latin, Italian and French have contributed many words to the English language, Latin and Ancient Greek roots are used in theology, biology, and medicine. By the late Roman Republic, Old Latin had been standardised into Classical Latin, Vulgar Latin was the colloquial form spoken during the same time and attested in inscriptions and the works of comic playwrights like Plautus and Terence. Late Latin is the language from the 3rd century. Later, Early Modern Latin and Modern Latin evolved, Latin was used as the language of international communication, scholarship, and science until well into the 18th century, when it began to be supplanted by vernaculars. Ecclesiastical Latin remains the language of the Holy See and the Roman Rite of the Catholic Church. Today, many students, scholars and members of the Catholic clergy speak Latin fluently and it is taught in primary, secondary and postsecondary educational institutions around the world. The language has been passed down through various forms, some inscriptions have been published in an internationally agreed, monumental, multivolume series, the Corpus Inscriptionum Latinarum. Authors and publishers vary, but the format is about the same, volumes detailing inscriptions with a critical apparatus stating the provenance, the reading and interpretation of these inscriptions is the subject matter of the field of epigraphy. The works of several hundred ancient authors who wrote in Latin have survived in whole or in part and they are in part the subject matter of the field of classics. The Cat in the Hat, and a book of fairy tales, additional resources include phrasebooks and resources for rendering everyday phrases and concepts into Latin, such as Meissners Latin Phrasebook. The Latin influence in English has been significant at all stages of its insular development. From the 16th to the 18th centuries, English writers cobbled together huge numbers of new words from Latin and Greek words, dubbed inkhorn terms, as if they had spilled from a pot of ink. Many of these words were used once by the author and then forgotten, many of the most common polysyllabic English words are of Latin origin through the medium of Old French. Romance words make respectively 59%, 20% and 14% of English, German and those figures can rise dramatically when only non-compound and non-derived words are included. Accordingly, Romance words make roughly 35% of the vocabulary of Dutch, Roman engineering had the same effect on scientific terminology as a whole
23.
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
24.
Hydroxy group
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A hydroxy or hydroxyl group is the entity with the formula OH. It contains oxygen bonded to hydrogen, in organic chemistry, alcohol and carboxylic acids contain hydroxy groups. The anion, called hydroxide, consists of a hydroxy group, according to IUPAC rules, the term hydroxyl refers to the radical OH only, while the functional group −OH is called hydroxy group. Water, alcohols, carboxylic acids, and many other hydroxy-containing compounds can be deprotonated readily and this behavior is rationalized by the disparate electronegativities of oxygen and hydrogen. Hydroxy-containing compounds engage in hydrogen bonding, which causes them to stick together, organic compounds, which are often poorly soluble in water, become water soluble when they contain two or more hydroxy groups, as illustrated by sugars and amino acid. The hydroxy group is pervasive in chemistry and biochemistry, many inorganic compounds contain hydroxy groups, including sulfuric acid, the chemical compound produced on the largest scale industrially. Hydroxy groups participate in the reactions that link simple biological molecules into long chains. The joining of a fatty acid to glycerol to form a triacylglycerol removes the −OH from the end of the fatty acid. The joining of two aldehyde sugars to form a disaccharide removes the −OH from the group at the aldehyde end of one sugar. The creation of a bond to link two amino acids to make a protein removes the −OH from the carboxy group of one amino acid. Hydroxyl radicals are highly reactive and undergo chemical reactions that make them short-lived, when biological systems are exposed to hydroxyl radicals, they can cause damage to cells, including those in humans, where they react with DNA, lipids, and proteins. In 2009, Indias Chandrayaan-1 satellite, NASAs Cassini spacecraft and the Deep Impact probe have each detected the presence of water by evidence of hydroxyl fragments on the Moon. As reported by Richard Kerr, A spectrometer detected an infrared absorption at a wavelength of 3.0 micrometers that only water or hydroxyl—a hydrogen, NASA also reported in 2009 that the LCROSS probe revealed an ultraviolet emission spectrum consistent with hydroxyl presence. The Venus Express orbiter sent back Venus science data from April 2006 until December 2014, results from Venus Express include the detection of hydroxyl in the atmosphere. Hydronium Ion Oxide Reece, Jane, Urry, Lisa, Cain, Michael, Wasserman, Steven, Minorsky, Peter, Jackson, berge, Susan, Golden, Brandy, Triglia, Logan
25.
Potassium
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Potassium is a chemical element with symbol K and atomic number 19. It was first isolated from potash, the ashes of plants, in the periodic table, potassium is one of the alkali metals. Potassium in nature only in ionic salts. It is found dissolved in sea water, and is part of many minerals, naturally occurring potassium is composed of three isotopes, of which 40K is radioactive. Traces of 40K are found in all potassium, and it is the most common radioisotope in the human body, Potassium is chemically very similar to sodium, the previous element in Group 1 of the periodic table. They have a similar energy, which allows for each atom to give up its sole outer electron. That they are different elements combine with the same anions to make similar salts was suspected in 1702. Most industrial applications of potassium exploit the high solubility in water of potassium compounds, heavy crop production rapidly depletes the soil of potassium, and this can be remedied with agricultural fertilizers containing potassium, accounting for 95% of global potassium chemical production. Potassium ions are necessary for the function of all living cells, fresh fruits and vegetables are good dietary sources of potassium. Potassium is the second least dense metal after lithium and it is a soft solid with a low melting point, and can be easily cut with a knife. Freshly cut potassium is silvery in appearance, but it begins to tarnish toward gray immediately on exposure to air, in a flame test, potassium and its compounds emit a lilac color with a peak emission wavelength of 766.5 nanometers. Neutral potassium atoms have 19 electrons, one more than the stable configuration of the noble gas argon. This process requires so little energy that potassium is readily oxidized by atmospheric oxygen, in contrast, the second ionization energy is very high, because removal of two electrons breaks the stable noble gas electronic configuration. Potassium therefore does not readily form compounds with the state of +2 or higher. Potassium is an active metal that reacts violently with oxygen in water. With oxygen it forms potassium peroxide, and with water potassium forms potassium hydroxide, the reaction of potassium with water is dangerous because of its violent exothermic character and the production of hydrogen gas. Hydrogen reacts again with atmospheric oxygen, producing water, which reacts with the remaining potassium and this reaction requires only traces of water, because of this, potassium and the liquid sodium-potassium — NaK — are potent desiccants that can be used to dry solvents prior to distillation. Because of the sensitivity of potassium to water and air, reactions with other elements are only in an inert atmosphere such as argon gas using air-free techniques
26.
Sodium
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Sodium is a chemical element with symbol Na and atomic number 11. It is a soft, silvery-white, highly reactive metal, Sodium is an alkali metal, being in group 1 of the periodic table, because it has a single electron in its outer shell that it readily donates, creating a positively charged atom—the Na+ cation. Its only stable isotope is 23Na, the free metal does not occur in nature, but must be prepared from compounds. Sodium is the sixth most abundant element in the Earths crust, Sodium was first isolated by Humphry Davy in 1807 by the electrolysis of sodium hydroxide. Among many other useful compounds, sodium hydroxide is used in soap manufacture, and sodium chloride is a de-icing agent. Sodium is an element for all animals and some plants. Sodium ions are the major cation in the fluid and as such are the major contributor to the ECF osmotic pressure. Loss of water from the ECF compartment increases the sodium concentration, isotonic loss of water and sodium from the ECF compartment decreases the size of that compartment in a condition called ECF hypovolemia. In nerve cells, the charge across the cell membrane enables transmission of the nerve impulse—an action potential—when the charge is dissipated. The melting and boiling points of sodium are lower than those of lithium but higher than those of the alkali metals potassium, rubidium. All of these high-pressure allotropes are insulators and electrides.3 nm, spin-orbit interactions involving the electron in the 3p orbital split the D line into two, at 589.0 and 589.6 nm, hyperfine structures involving both orbitals cause many more lines. Twenty isotopes of sodium are known, but only 23Na is stable, 23Na is created in the carbon-burning process in stars by fusing two carbon atoms together, this requires temperatures above 600 megakelvins and a star of at least three solar masses. Two nuclear isomers have been discovered, the one being 24mNa with a half-life of around 20.2 milliseconds. Sodium atoms have 11 electrons, one more than the stable configuration of the noble gas neon. This process requires so little energy that sodium is oxidized by giving up its 11th electron. In contrast, the ionization energy is very high, because the 10th electron is closer to the nucleus than the 11th electron. As a result, sodium usually forms ionic compounds involving the Na+ cation, the most common oxidation state for sodium is +1. It is generally less reactive than potassium and more reactive than lithium, Sodium metal is highly reducing, with the reduction of sodium ions requiring −2.71 volts, though potassium and lithium have even more negative potentials
27.
Calcium
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Calcium is a chemical element with symbol Ca and atomic number 20. Calcium is a soft grayish-yellow alkaline earth metal, fifth-most-abundant element by mass in the Earths crust, the ion Ca2+ is also the fifth-most-abundant dissolved ion in seawater by both molarity and mass, after sodium, chloride, magnesium, and sulfate. Free calcium metal is too reactive to occur in nature, Calcium is produced in supernova nucleosynthesis. Calcium is a trace element in living organisms. It is the most abundant metal by mass in animals, and it is an important constituent of bone, teeth. In cell biology, the movement of the calcium ion into, Calcium carbonate and calcium citrate are often taken as dietary supplements. Calcium is on the World Health Organizations List of Essential Medicines, Calcium has a wide variety of applications, almost all of which are associated with calcium compounds and salts. Calcium metal is used as a deoxidizer, desulfurizer, and decarbonizer for production of ferrous and nonferrous alloys. In steelmaking and production of iron, Ca reacts with oxygen, Calcium carbonate is used in manufacturing cement and mortar, lime, limestone and aids in production in the glass industry. It also has chemical and optical uses as mineral specimens in toothpastes, Calcium hydroxide solution is used to detect the presence of carbon dioxide in a gas sample bubbled through a solution. The solution turns cloudy where CO2 is present, Calcium arsenate is used in insecticides. Calcium carbide is used to make acetylene gas and various plastics, Calcium chloride is used in ice removal and dust control on dirt roads, as a conditioner for concrete, as an additive in canned tomatoes, and to provide body for automobile tires. Calcium citrate is used as a food preservative, Calcium cyclamate is used as a sweetening agent in several countries. In the United States, it has been outlawed as a suspected carcinogen, Calcium gluconate is used as a food additive and in vitamin pills. Calcium hypochlorite is used as a swimming pool disinfectant, as an agent, as an ingredient in deodorant. Calcium permanganate is used in rocket propellant, textile production, as a water sterilizing agent. Calcium phosphate is used as a supplement for animal feed, fertilizer, in production for dough and yeast products, in the manufacture of glass. Calcium phosphide is used in fireworks, rodenticide, torpedoes, Calcium sulfate is used as common blackboard chalk, as well as, in its hemihydrate form, Plaster of Paris
28.
Barium
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Barium is a chemical element with symbol Ba and atomic number 56. It is the element in Group 2, a soft silvery metallic alkaline earth metal. Because of its chemical reactivity, barium is never found in nature as a free element. Its hydroxide, known in history as baryta, does not occur as a mineral. The most common naturally occurring minerals of barium are barite and witherite, the barium name originates from the alchemical derivative baryta, from Greek βαρύς, meaning heavy. Baric is the form of barium. Barium was identified as a new element in 1774, but not reduced to a metal until 1808 with the advent of electrolysis, historically, it was used as a getter for vacuum tubes. It is a component of YBCO and electroceramics, and is added to steel, Barium compounds are added to fireworks to impart a green color. Barium sulfate is used as an additive to oil well drilling fluid, as well as in a purer form. The soluble barium ion and soluble compounds are poisonous, and have used as rodenticides. Barium is a soft, silvery-white metal, with a slight golden shade when ultrapure, the silvery-white color of barium metal rapidly vanishes upon oxidation in air yielding a dark gray oxide layer. Barium has a specific weight and good electrical conductivity. Ultrapure barium is very difficult to prepare, and therefore properties of barium have not been accurately measured yet. At room temperature and pressure, barium has a cubic structure, with a barium–barium distance of 503 picometers. It is a soft metal with a Mohs hardness of 1.25. Its melting temperature of 1,000 K is intermediate between those of the strontium and heavier radium, however, its boiling point of 2,170 K exceeds that of strontium. The density is again intermediate between those of strontium and radium, Barium is chemically similar to magnesium, calcium, and strontium, but even more reactive. It always exhibits the oxidation state of +2, except in a few rare, reactions with chalcogens are highly exothermic, the reaction with oxygen or air occurs at room temperature, and therefore barium is stored under oil or in an inert atmosphere
29.
Rubidium
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Rubidium is a chemical element with symbol Rb and atomic number 37. Rubidium is a soft, silvery-white metallic element of the metal group. Elemental rubidium is highly reactive, with similar to those of other alkali metals. German chemists Robert Bunsen and Gustav Kirchhoff discovered rubidium in 1861 by the developed technique. Rubidiums compounds have various chemical and electronic applications, rubidium metal is easily vaporized and has a convenient spectral absorption range, making it a frequent target for laser manipulation of atoms. Rubidium is not a nutrient for any living organisms. However, rubidium ions have the charge as potassium ions. Rubidium is a soft, ductile, silvery-white metal. It is the second most electropositive of the alkali metals. Similar to other metals, rubidium metal reacts violently with water. As with potassium and caesium, this reaction is vigorous enough to ignite the hydrogen gas it produces. Rubidium has also reported to ignite spontaneously in air. It forms amalgams with mercury and alloys with gold, iron, caesium, sodium, and potassium, rubidium has a very low ionization energy of only 406 kJ/mol. Rubidium and potassium show a very similar purple color in the flame test, rubidium silver iodide has the highest room temperature conductivity of any known ionic crystal, a property exploited in thin film batteries and other applications. Rubidium forms a number of oxides when exposed to air, including rubidium monoxide, Rb6O, rubidium forms salts with halides, producing rubidium fluoride, rubidium chloride, rubidium bromide, and rubidium iodide. Although rubidium is monoisotopic, rubidium in the Earths crust is composed of two isotopes, the stable 85Rb and the radioactive 87Rb, natural rubidium is radioactive, with specific activity of about 670 Bq/g, enough to significantly expose a photographic film in 110 days. Twenty four additional rubidium isotopes have been synthesized with half-lives of less than 3 months, Rubidium-87 has a half-life of 48. 8×109 years, which is more than three times the age of the universe of ×109 years, making it a primordial nuclide. It readily substitutes for potassium in minerals, and is fairly widespread
30.
Caesium
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Caesium or cesium is a chemical element with symbol Cs and atomic number 55. It is a soft, silvery-gold alkali metal with a point of 28.5 °C. Caesium is a metal and has physical and chemical properties similar to those of rubidium and potassium. The metal is extremely reactive and pyrophoric, reacting with water even at −116 °C, Caesium is one of the most reactive elements of all, even more reactive than fluorine, the most reactive nonmetal. It is the least electronegative element, with a value of 0.79 on the Pauling scale and it has only one stable isotope, caesium-133. Caesium is mined mostly from pollucite, while the radioisotopes, especially caesium-137, the German chemist Robert Bunsen and physicist Gustav Kirchhoff discovered caesium in 1860 by the newly developed method of flame spectroscopy. The first small-scale applications for caesium were as a getter in vacuum tubes, since then, caesium has been widely used in highly accurate atomic clocks. The radioactive isotope caesium-137 has a half-life of about 30 years and is used in applications, industrial gauges. Although the element is only toxic, the metal is a hazardous material. It is a ductile, pale metal, which darkens in the presence of trace amounts of oxygen. When in the presence of oil, it loses its metallic lustre and takes on a duller. It has a point of 28.4 °C, making it one of the few elemental metals that are liquid near room temperature. Mercury is the elemental metal with a known melting point lower than caesium. In addition, the metal has a low boiling point,641 °C. Its compounds burn with a blue or violet colour, Caesium forms alloys with the other alkali metals, gold, and mercury. At temperatures below 650 °C, it does not alloy with cobalt, iron, molybdenum, nickel, platinum, tantalum and it forms well-defined intermetallic compounds with antimony, gallium, indium, and thorium, which are photosensitive. It mixes with all the alkali metals, the alloy with a molar distribution of 41% caesium, 47% potassium. A few amalgams have been studied, CsHg 2 is black with a metallic lustre, while CsHg is golden-coloured
31.
Aluminium
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Aluminium or aluminum is a chemical element in the boron group with symbol Al and atomic number 13. It is a silvery-white, soft, nonmagnetic, ductile metal, Aluminium metal is so chemically reactive that native specimens are rare and limited to extreme reducing environments. Instead, it is combined in over 270 different minerals. The chief ore of aluminium is bauxite, Aluminium is remarkable for the metals low density and its ability to resist corrosion through the phenomenon of passivation. Aluminium and its alloys are vital to the industry and important in transportation and structures, such as building facades. The oxides and sulfates are the most useful compounds of aluminium, despite its prevalence in the environment, no known form of life uses aluminium salts metabolically, but aluminium is well tolerated by plants and animals. Because of these salts abundance, the potential for a role for them is of continuing interest. Aluminium is a soft, durable, lightweight, ductile. It is nonmagnetic and does not easily ignite, a fresh film of aluminium serves as a good reflector of visible light and an excellent reflector of medium and far infrared radiation. The yield strength of aluminium is 7–11 MPa, while aluminium alloys have yield strengths ranging from 200 MPa to 600 MPa. Aluminium has about one-third the density and stiffness of steel and it is easily machined, cast, drawn and extruded. Aluminium atoms are arranged in a cubic structure. Aluminium has an energy of approximately 200 mJ/m2. Aluminium is a thermal and electrical conductor, having 59% the conductivity of copper. Aluminium is capable of superconductivity, with a critical temperature of 1.2 kelvin. Aluminium is the most common material for the fabrication of superconducting qubits, the strongest aluminium alloys are less corrosion resistant due to galvanic reactions with alloyed copper. This corrosion resistance is reduced by aqueous salts, particularly in the presence of dissimilar metals. In highly acidic solutions, aluminium reacts with water to form hydrogen, primarily because it is corroded by dissolved chlorides, such as common sodium chloride, household plumbing is never made from aluminium
32.
Magnesium
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Magnesium is a chemical element with symbol Mg and atomic number 12. Magnesium is the ninth most abundant element in the universe and it is produced in large, aging stars from the sequential addition of three helium nuclei to a carbon nucleus. When such stars explode as supernovas, much of the magnesium is expelled into the medium where it may recycle into new star systems. Magnesium is the eighth most abundant element in the Earths crust and the fourth most common element in the Earth, making up 13% of the planets mass and it is the third most abundant element dissolved in seawater, after sodium and chlorine. Magnesium occurs naturally only in combination with elements, where it invariably has a +2 oxidation state. The free element can be produced artificially, and is highly reactive, the free metal burns with a characteristic brilliant-white light. The metal is now obtained mainly by electrolysis of magnesium salts obtained from brine, Magnesium is less dense than aluminium, and the alloy is prized for its combination of lightness and strength. Magnesium is the eleventh most abundant element by mass in the body and is essential to all cells. Magnesium ions interact with polyphosphate compounds such as ATP, DNA, hundreds of enzymes require magnesium ions to function. Magnesium compounds are used medicinally as common laxatives, antacids, elemental magnesium is a gray-white lightweight metal, two-thirds the density of aluminium. Magnesium has the lowest melting and the lowest boiling point 1,363 K of all the alkaline earth metals, Magnesium reacts with water at room temperature, though it reacts much more slowly than calcium, a similar group 2 metal. When submerged in water, hydrogen bubbles form slowly on the surface of the metal—though, if powdered, the reaction occurs faster with higher temperatures. Magnesiums reversible reaction with water can be harnessed to store energy, Magnesium also reacts exothermically with most acids such as hydrochloric acid, producing the metal chloride and hydrogen gas, similar to the HCl reaction with aluminium, zinc, and many other metals. Magnesium is highly flammable, especially when powdered or shaved into thin strips, flame temperatures of magnesium and magnesium alloys can reach 3,100 °C, although flame height above the burning metal is usually less than 300 mm. Once ignited, such fires are difficult to extinguish, with combustion continuing in nitrogen, carbon dioxide, Magnesium may also be used as an igniter for thermite, a mixture of aluminium and iron oxide powder that ignites only at a very high temperature. When burning in air, magnesium produces a light that includes strong ultraviolet wavelengths. Magnesium powder was used for illumination in the early days of photography. Later, magnesium filament was used in electrically ignited single-use photography flashbulbs, Magnesium powder is used in fireworks and marine flares where a brilliant white light is required
33.
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
34.
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
35.
Chromium
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Chromium is a chemical element with symbol Cr and atomic number 24. It is the first element in Group 6 and it is a steely-grey, lustrous, hard and brittle metal which takes a high polish, resists tarnishing, and has a high melting point. The name of the element is derived from the Greek word χρῶμα, chrōma, meaning color, Chromium metal is of high value for its high corrosion resistance and hardness. A major development was the discovery that steel could be highly resistant to corrosion and discoloration by adding metallic chromium to form stainless steel. Stainless steel and chrome plating together comprise 85% of the commercial use, trivalent chromium ion is an essential nutrient in trace amounts in humans for insulin, sugar and lipid metabolism, although the issue is debated. While chromium metal and Cr ions are not considered toxic, hexavalent chromium is toxic and carcinogenic, abandoned chromium production sites often require environmental cleanup. Chromium is remarkable for its properties, it is the only elemental solid which shows antiferromagnetic ordering at room temperature. Above 38 °C, it changes to paramagnetic, Chromium metal left standing in air is passivated by oxidation, forming a thin, protective, surface layer. This layer is a structure only a few molecules thick. It is very dense, and prevents the diffusion of oxygen into the underlying metal and this is different from the oxide that forms on iron and carbon steel, through which elemental oxygen continues to migrate, reaching the underlying material to cause incessant rusting. Passivation can be enhanced by short contact with oxidizing acids like nitric acid, passivated chromium is stable against acids. Passivation can be removed with a reducing agent that destroys the protective oxide layer on the metal. Chromium metal treated in this way readily dissolves in weak acids, Chromium, unlike such metals as iron and nickel, does not suffer from hydrogen embrittlement. However, it suffer from nitrogen embrittlement, reacting with nitrogen from air. Chromium is the 22nd most abundant element in Earths crust with a concentration of 100 ppm. Chromium compounds are found in the environment from the erosion of chromium-containing rocks, Chromium is mined as chromite ore. About two-fifths of the ores and concentrates in the world are produced in South Africa, while Kazakhstan, India, Russia. Untapped chromite deposits are plentiful, but geographically concentrated in Kazakhstan, although rare, deposits of native chromium exist
36.
Titanium
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Titanium is a chemical element with symbol Ti and atomic number 22. It is a transition metal with a silver color, low density. Titanium is resistant to corrosion in sea water, aqua regia, titanium was discovered in Cornwall, Great Britain, by William Gregor in 1791, and it is named by Martin Heinrich Klaproth for the Titans of Greek mythology. The metal is extracted from its principal mineral ores by the Kroll, the most common compound, titanium dioxide, is a popular photocatalyst and is used in the manufacture of white pigments. Other compounds include titanium tetrachloride, a component of smoke screens and catalysts, and titanium trichloride, the two most useful properties of the metal are corrosion resistance and strength-to-density ratio, the highest of any metallic element. In its unalloyed condition, titanium is as strong as some steels, there are two allotropic forms and five naturally occurring isotopes of this element, 46Ti through 50Ti, with 48Ti being the most abundant. Although they have the number of valence electrons and are in the same group in the periodic table. As a metal, titanium is recognized for its high strength-to-weight ratio and it is a strong metal with low density that is quite ductile, lustrous, and metallic-white in color. The relatively high melting point makes it useful as a refractory metal and it is paramagnetic and has fairly low electrical and thermal conductivity. Commercial grades of titanium have ultimate tensile strength of about 434 MPa, equal to that of common, low-grade steel alloys, titanium is 60% denser than aluminium, but more than twice as strong as the most commonly used 6061-T6 aluminium alloy. Certain titanium alloys achieve tensile strengths of over 1400 MPa, however, titanium loses strength when heated above 430 °C. Titanium is not as hard as some grades of heat-treated steel, it is non-magnetic, machining requires precautions, because the material might gall unless sharp tools and proper cooling methods are used. Like steel structures, those made from titanium have a limit that guarantees longevity in some applications. The metal is an allotrope of an hexagonal α form that changes into a body-centered cubic β form at 882 °C. The specific heat of the α form increases dramatically as it is heated to this transition temperature but then falls, similar to zirconium and hafnium, an additional omega phase exists, which is thermodynamically stable at high pressures, but metastable at ambient pressures. This phase is usually hexagonal or trigonal and can be considered to be due to a soft longitudinal acoustic phonon of the β phase causing collapse of planes of atoms, like aluminium and magnesium, titanium metal and its alloys oxidize immediately upon exposure to air. Titanium readily reacts with oxygen at 1,200 °C in air and it is, however, slow to react with water and air at ambient temperatures because it forms a passive oxide coating that protects the bulk metal from further oxidation. When it first forms, this layer is only 1–2 nm thick but continues to grow slowly
37.
Lithium
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Lithium is a chemical element with the symbol Li and atomic number 3. It is a soft, silver-white metal belonging to the metal group of chemical elements. Under standard conditions, it is the lightest metal and the least dense solid element, like all alkali metals, lithium is highly reactive and flammable. For this reason, it is stored in mineral oil. When cut open, it exhibits a metallic luster, but contact with moist air corrodes the surface quickly to a silvery gray. Because of its reactivity, lithium never occurs freely in nature, and instead, appears only in compounds. Lithium occurs in a number of minerals, but due to its solubility as an ion, is present in ocean water and is commonly obtained from brines. On a commercial scale, lithium is isolated electrolytically from a mixture of lithium chloride, the nucleus of the lithium atom verges on instability, since the two stable lithium isotopes found in nature have among the lowest binding energies per nucleon of all stable nuclides. Because of its relative instability, lithium is less common in the solar system than 25 of the first 32 chemical elements even though the nuclei are very light in atomic weight. For related reasons, lithium has important links to nuclear physics, the transmutation of lithium atoms to helium in 1932 was the first fully man-made nuclear reaction, and lithium-6 deuteride serves as a fusion fuel in staged thermonuclear weapons. These uses consume more than three quarters of lithium production, Lithium is found in variable amounts in foods, primary food sources are grains and vegetables, in some areas, the drinking water also provides significant amounts of the element. Human dietary lithium intakes depend on location and the type of foods consumed, traces of lithium were detected in human organs and fetal tissues already in the late 19th century, leading to early suggestions as to possible specific functions in the organism. However, it took another century until evidence for the essentiality of lithium became available, in studies conducted from the 1970s to the 1990s, rats and goats maintained on low-lithium rations were shown to exhibit higher mortalities as well as reproductive and behavioral abnormalities. Lithium appears to play an important role during the early fetal development as evidenced by the high lithium contents of the embryo during the early gestational period. The available experimental evidence now appears to be sufficient to accept lithium as essential, the lithium ion Li+ administered as any of several lithium salts has proven to be useful as a mood-stabilizing drug in the treatment of bipolar disorder in humans. Like the other metals, lithium has a single valence electron that is easily given up to form a cation. Because of this, lithium is a conductor of heat and electricity as well as a highly reactive element. Lithiums low reactivity is due to the proximity of its electron to its nucleus
38.
Silicon
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Silicon is a chemical element with symbol Si and atomic number 14. A hard and brittle crystalline solid with a metallic luster. It is a member of group 14 in the table, along with carbon above it and germanium, tin, lead. It is not very reactive, although more reactive than germanium, Silicon is the eighth most common element in the universe by mass, but very rarely occurs as the pure element in the Earths crust. It is most widely distributed in dusts, sands, planetoids, over 90% of the Earths crust is composed of silicate minerals, making silicon the second most abundant element in the Earths crust after oxygen. Most silicon is used commercially without being separated, and often with little processing of the natural minerals, such use includes industrial construction with clays, silica sand, and stone. Silicate is used in Portland cement for mortar and stucco, and mixed with sand and gravel to make concrete for walkways, foundations. Silicates are used in whiteware ceramics such as porcelain, and in traditional quartz-based soda-lime glass, Silicon compounds such as silicon carbide are used as abrasives and components of high-strength ceramics. Elemental silicon also has an impact on the modern world economy. Most free silicon is used in the refining, aluminium-casting. Silicon is the basis of the widely used synthetic polymers called silicones, Silicon is an essential element in biology, although only tiny traces are required by animals. However, various sea sponges and microorganisms, such as diatoms and radiolaria, silica is deposited in many plant tissues, such as in the bark and wood of Chrysobalanaceae and the silica cells and silicified trichomes of Cannabis sativa, horsetails and many grasses. Silicon is a solid at room temperature, with a point of 1,414 °C. Like water, it has a density in a liquid state than in a solid state and it expands when it freezes. With a relatively high conductivity of 149 W·m−1·K−1, silicon conducts heat well. In its crystalline form, pure silicon has a gray color, like germanium, silicon is rather strong, very brittle, and prone to chipping. Silicon, like carbon and germanium, crystallizes in a cubic crystal structure with a lattice spacing of 0.5430710 nm. The outer electron orbital of silicon, like that of carbon, has four valence electrons, the 1s, 2s, 2p and 3s subshells are completely filled while the 3p subshell contains two electrons out of a possible six
39.
Ferric
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Ferric refers to iron-containing materials or compounds. In chemistry the term is reserved for iron with an number of +3. On the other hand, ferrous refers to iron with oxidation number of +2, iron is usually the most stable form of iron in air, as illustrated by the pervasiveness of rust, an insoluble iron-containing material. The word ferric is derived from the Latin word ferrum for iron, examples include iron-sulfur clusters, oxyhemoglobin, ferritin, and the cytochromes. The bioavailability of iron is of great interest because all forms of life require iron. Iron-deficiency anemia illustrates the problems resulting from low iron intake, many foods contain soluble iron compounds and are therefore necessary for good nutrition. The low bioavailability of iron affects all forms of life, bacteria secrete iron-attracting agents called siderophores that form soluble compounds of iron that can be reabsorbed into the cell and used in building iron-containing metalloproteins. The impact of increasing the bioavailability of iron was famously demonstrated by an experiment where an area of the ocean surface was sprayed with iron salts. After several days, the phytoplankton within the treated area bloomed to such an extent that the effect was visible from outer space and this fertilizing process has been proposed as a means to mitigate the carbon dioxide content of the atmosphere. Ferric iron mitigates the eutrophication of lakes by reducing the bioavailability of phosphorus in the water, mitigation arises because ferric phosphate is insoluble. Like iron, phosphate is often a limiting nutrient, and its reduction in concentration from solution limits the growth of algae, in water, ferric iron forms compounds that are often insoluble, at least near neutral pH. A salt of ferric iron hydrolyzes water and produces iron oxide-hydroxides while contributing hydrogen ions to the solution, in contrast, typical Na+ salts dissolve in water without lowering the pH. Aluminium behaves similarly to ferric ion, rust, a mixture of ferric hydroxide compounds, illustrates the low solubility of ferric ions in water. Various reagents cause rust to dissolve even at neutral pH and these ligands include EDTA, which forms a chelate complex with the ion, displacing the hydroxide and oxide ligands that comprise rust. For this reason, EDTA is often used to iron deposits or to deliver soluble iron in fertilizers. Citrate also solubilizes ferric ion at neutral pH, although its complexes are less stable than those of EDTA, Ferric iron is a d5 center, meaning that the metal has five valence electrons in the 3d orbital shell. The magnetism of ferric compounds is determined by these five electrons. Usually ferric ions are surrounded by six ligands arranged in octahedron, sometimes three and sometimes as many as seven ligands are observed
40.
Zinnwaldite
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Zinnwaldite, KLiFeAlO102, potassium lithium iron aluminium silicate hydroxide fluoride is a silicate mineral in the mica group. The IMA status is as a series between siderophyllite and polylithionite and not considered a mineral species. It was first described in 1845 in Zinnwald/Cinovec on the German-Czech Republic border and it occurs in greisens, pegmatite, and quartz veins often associated with tin ore deposits. It is commonly associated with topaz, cassiterite, wolframite, lepidolite, spodumene, beryl, tourmaline, and fluorite
41.
Clintonite
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Not to be confused with the political term Clintonite Clintonite is a calcium magnesium aluminium phyllosilicate mineral. It is a member of the group of micas and the subgroup often referred to as the brittle micas. Clintonite has the formula, Ca3O102. Like other micas and chlorites, clintonite is monoclinic in crystal form and has a perfect cleavage parallel to the flat surface of the plates or scales. The Mohs hardness of clintonite is 6.5, and the gravity is 3.0 to 3.1. It occurs as variably colored, colorless, green, yellow, red, to reddish-brown masses, Clintonite and its iron-rich variety xanthophyllite are sometimes considered the calcium analogues of the phlogopites. Typical formation environment is in serpentinized dolomitic limestones and contact metamorphosed skarns and it occurs with talc, spinel, grossular, vesuvianite, clinopyroxene, monticellite, chondrodite, phlogopite, chlorite, quartz, calcite and dolomite. Clintonite was first described in 1843 for an occurrence in Orange County and it was named for De Witt Clinton. List of minerals List of minerals named after people
42.
Illite
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Illite is a non-expanding clay crystalline mineral. Illite is a secondary mineral precipitate phyllosilicate or layered alumino-silicate and its structure is a 2,1 clay of silica tetrahedron – alumina octahedron – silica tetrahedron layers. The space between individual clay crystals is occupied by poorly hydrated potassium cations which is responsible for the absence of swelling, structurally, illite is quite similar to muscovite with slightly more silicon, magnesium, iron, and water and slightly less tetrahedral aluminium and interlayer potassium. The chemical formula is given as 24O10, but there is considerable ion substitution and it occurs as aggregates of small monoclinic grey to white crystals. Due to the size, positive identification usually requires x-ray diffraction or SEM-EDS analysis. Illite occurs as a product of muscovite and feldspar in weathering and hydrothermal environments. It is common in sediments, soils, and argillaceous sedimentary rocks as well as in low grade metamorphic rocks. The iron rich member of the group, glauconite, in sediments can be differentiated by x-ray analysis. The cation-exchange capacity of illite is smaller than that of smectite but higher than that of kaolinite, illite was first described for occurrences in the Maquoketa shale in Calhoun County, Illinois, US, in 1937. The name was derived from its location in Illinois. Illite is also called hydromica or hydromuscovite, brammallite is a sodium rich analogue. Avalite is a chromium bearing variety which has been described form Mt. Avala, Belgrade, the crystallinity of illite has been used as an indicator of metamorphic grade in clay-bearing rocks metamorphosed under conditions between diagenesis and low-grade metamorphism. With increasing temperature, illite is thought to undergo a transformation into muscovite,437 pp, see Chapter 3, Soil Mineralogy, p.32
43.
Phengite
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Phengite is a series name for dioctahedral micas of composition K224O10, similar to muscovite but with addition of magnesium. It is a recognized mineral name representing the series between muscovite and celadonite. The silica content of phengite has been proposed as a geobarometer for the metamorphism of low grade schists, glossary of Geology, Fifth Edition, Eds. Jackson, American Geological Institute,2005 von Kobell, Franz Tafeln zur Bestimmung des Mineralien, 5th edition, guidotti, Charles V. Micas in metamorphic Rocks, reviews in Mineralogy,13, 357-467. A high-pressure Fourier-transform infrared study of the interlayer and Si-O stretching region in phengite-2M1. Cibin, G. G. Cinque, A. Marcelli, A. Mottana, & R. Sassi, The octahedral sheet of metamorphic 2M1-phengites, a combined EMPA and AXANES study, American Mineralogist 93, 414-425
44.
Igneous rock
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Igneous rock, or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rock is formed through the cooling and solidification of magma or lava, the magma can be derived from partial melts of existing rocks in either a planets mantle or crust. Typically, the melting is caused by one or more of three processes, an increase in temperature, a decrease in pressure, or a change in composition, solidification into rock occurs either below the surface as intrusive rocks or on the surface as extrusive rocks. Igneous rock may form with crystallization to form granular, crystalline rocks, Igneous and metamorphic rocks make up 90–95% of the top 16 km of the Earths crust by volume. Igneous rocks form about 15% of the Earths current land surface, most of the Earths oceanic crust is made of igneous rock. In terms of modes of occurrence, igneous rocks can be either intrusive or extrusive, the mineral grains in such rocks can generally be identified with the naked eye. Intrusive rocks can also be classified according to the shape and size of the intrusive body, typical intrusive formations are batholiths, stocks, laccoliths, sills and dikes. When the magma solidifies within the earths crust, it cools slowly forming coarse textured rocks, such as granite, gabbro, the central cores of major mountain ranges consist of intrusive igneous rocks, usually granite. When exposed by erosion, these cores may occupy huge areas of the Earths surface, intrusive igneous rocks that form at depth within the crust are termed plutonic rocks and are usually coarse-grained. Intrusive igneous rocks that form near the surface are termed subvolcanic or hypabyssal rocks, hypabyssal rocks are less common than plutonic or volcanic rocks and often form dikes, sills, laccoliths, lopoliths, or phacoliths. Extrusive igneous rocks, also known as rocks, are formed at the crusts surface as a result of the partial melting of rocks within the mantle. Extrusive igneous rocks cool and solidify quicker than intrusive igneous rocks and they are formed by the cooling of molten magma on the earths surface. The magma, which is brought to the surface through fissures or volcanic eruptions, hence such rocks are smooth, crystalline and fine-grained. Basalt is an extrusive igneous rock and forms lava flows, lava sheets. Some kinds of basalt solidify to form long polygonal columns, the Giants Causeway in Antrim, Northern Ireland is an example. The molten rock, with or without suspended crystals and gas bubbles, is called magma and it rises because it is less dense than the rock from which it was created. When magma reaches the surface from beneath water or air, it is called lava, eruptions of volcanoes into air are termed subaerial, whereas those occurring underneath the ocean are termed submarine. Black smokers and mid-ocean ridge basalt are examples of volcanic activity
45.
Metamorphic rock
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Metamorphic rocks arise from the transformation of existing rock types, in a process called metamorphism, which means change in form. The original rock is subjected to heat and pressure, causing profound physical and/or chemical change, the protolith may be a sedimentary, an igneous, or even an existing type of metamorphic rock. Metamorphic rocks make up a part of the Earths crust. They are classified by texture and by chemical and mineral assemblage and they may be formed simply by being deep beneath the Earths surface, subjected to high temperatures and the great pressure of the rock layers above it. They can form from tectonic processes such as continental collisions, which cause horizontal pressure and they are also formed when rock is heated up by the intrusion of hot molten rock called magma from the Earths interior. The study of rocks provides information about the temperatures and pressures that occur at great depths within the Earths crust. Some examples of rocks are gneiss, slate, marble, schist. Metamorphic minerals are those that only at the high temperatures and pressures associated with the process of metamorphism. These minerals, known as index minerals, include sillimanite, kyanite, staurolite, andalusite, and some garnet. Other minerals, such as olivines, pyroxenes, amphiboles, micas, feldspars, and quartz, may be found in metamorphic rocks and these minerals formed during the crystallization of igneous rocks. They are stable at temperatures and pressures and may remain chemically unchanged during the metamorphic process. However, all minerals are only within certain limits. The change in the size of the rock during the process of metamorphism is called recrystallization. Both high temperatures and pressures contribute to recrystallization, high temperatures allow the atoms and ions in solid crystals to migrate, thus reorganizing the crystals, while high pressures cause solution of the crystals within the rock at their point of contact. The layering within metamorphic rocks is called foliation, and it occurs when a rock is being shortened along one axis during recrystallization. This causes the platy or elongated crystals of minerals, such as mica and chlorite and this results in a banded, or foliated rock, with the bands showing the colors of the minerals that formed them. Textures are separated into foliated and non-foliated categories, foliated rock is a product of differential stress that deforms the rock in one plane, sometimes creating a plane of cleavage. For example, slate is a metamorphic rock, originating from shale
46.
Sedimentary
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Sedimentary rocks are types of rock that are formed by the deposition and subsequent cementation of that material at the Earths surface and within bodies of water. Sedimentation is the name for processes that cause mineral and/or organic particles to settle in place. The particles that form a rock by accumulating are called sediment. Sedimentation may also occur as minerals precipitate from solution or shells of aquatic creatures settle out of suspension. The sedimentary rock cover of the continents of the Earths crust is extensive, sedimentary rocks are only a thin veneer over a crust consisting mainly of igneous and metamorphic rocks. Sedimentary rocks are deposited in layers as strata, forming a structure called bedding, sedimentary rocks are also important sources of natural resources like coal, fossil fuels, drinking water or ores. The study of the sequence of rock strata is the main source for an understanding of the Earths history, including palaeogeography, paleoclimatology. The scientific discipline that studies the properties and origin of rocks is called sedimentology. Sedimentology is part of both geology and physical geography and overlaps partly with other disciplines in the Earth sciences, such as pedology, geomorphology, geochemistry, sedimentary rocks have also been found on Mars. Clastic sedimentary rocks are composed of rock fragments that were cemented by silicate minerals. Clastic rocks are composed largely of quartz, feldspar, rock fragments, clay minerals, and mica, any type of mineral may be present, clastic sedimentary rocks, are subdivided according to the dominant particle size. Most geologists use the Udden-Wentworth grain size scale and divide unconsolidated sediment into three fractions, gravel, sand, and mud and this tripartite subdivision is mirrored by the broad categories of rudites, arenites, and lutites, respectively, in older literature. The subdivision of these three categories is based on differences in clast shape, conglomerates and breccias), composition. Conglomerates are dominantly composed of rounded gravel, while breccias are composed of dominantly angular gravel, composition of framework grains The relative abundance of sand-sized framework grains determines the first word in a sandstone name. Naming depends on the dominance of the three most abundant components quartz, feldspar, or the lithic fragments that originated from other rocks, all other minerals are considered accessories and not used in the naming of the rock, regardless of abundance. Clean sandstones with open space are called arenites. Muddy sandstones with abundant muddy matrix are called wackes, six sandstone names are possible using the descriptors for grain composition and the amount of matrix. Mudrocks are sedimentary rocks composed of at least 50% silt- and clay-sized particles and these relatively fine-grained particles are commonly transported by turbulent flow in water or air, and deposited as the flow calms and the particles settle out of suspension
47.
Granite
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Granite is a common type of felsic intrusive igneous rock that is granular and phaneritic in texture. Granites can be white, pink, or gray in color. The word granite comes from the Latin granum, a grain, in reference to the structure of such a holocrystalline rock. By definition, granite is a rock with at least 20% quartz. The term granitic means granite-like and is applied to granite and a group of igneous rocks with similar textures and slight variations in composition. Occasionally some individual crystals are larger than the groundmass, in case the texture is known as porphyritic. A granitic rock with a texture is known as a granite porphyry. Granitoid is a general, descriptive field term for lighter-colored, coarse-grained igneous rocks, petrographic examination is required for identification of specific types of granitoids. The extrusive igneous rock equivalent of granite is rhyolite, Granite is nearly always massive, hard and tough, and therefore it has gained widespread use throughout human history, and more recently as a construction stone. The average density of granite is between 2.65 and 2.75 g/cm3, its compressive strength usually lies above 200 MPa, and its viscosity near STP is 3–6 •1019 Pa·s. The melting temperature of dry granite at ambient pressure is 1215–1260 °C, it is reduced in the presence of water. Granite has poor primary permeability, but strong secondary permeability, true granite according to modern petrologic convention contains both plagioclase and alkali feldspars. When a granitoid is devoid or nearly devoid of plagioclase, the rock is referred to as alkali feldspar granite, when a granitoid contains less than 10% orthoclase, it is called tonalite, pyroxene and amphibole are common in tonalite. A granite containing both muscovite and biotite micas is called a binary or two-mica granite, two-mica granites are typically high in potassium and low in plagioclase, and are usually S-type granites or A-type granites. A worldwide average of the composition of granite, by weight percent, based on 2485 analyses. Much of it was intruded during the Precambrian age, it is the most abundant basement rock that underlies the relatively thin veneer of the continents. Outcrops of granite tend to form tors and rounded massifs, granites sometimes occur in circular depressions surrounded by a range of hills, formed by the metamorphic aureole or hornfels. Granite often occurs as small, less than 100 km² stock masses
48.
Pegmatite
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A pegmatite is a holocrystalline, intrusive igneous rock composed of interlocking phaneritic crystals usually larger than 2.5 cm in size, such rocks are referred to as pegmatitic. The word pegmatite derives from Homeric Greek, πεγνυμι, which means “to bind together”, in reference to the crystals of quartz. Most pegmatites are composed of quartz, feldspar and mica, having a similar composition as granite. Crystal size is the most striking feature of pegmatites, with usually over 5 cm in size. Individual crystals over 10 metres long have been found, and many of the worlds largest crystals were found within pegmatites and these include, spodumene, microcline, beryl, and tourmaline. Similarly, crystal texture and form within pegmatitic rock may be taken to extreme size, perthite feldspar within a pegmatite often shows gigantic perthitic texture visible to the naked eye. The single feature that is diagnostic to all pegmatites is their large size crystal components, Pegmatite bodies are usually of minor size compared to typical intrusive rock bodies. Pegmatite body size is on the order of magnitude of one to a few hundred meters, compared to typical igneous rocks they are rather inhomogeneous and may show zones with different mineral assemblages. Crystal size and mineral assemblages are usually oriented parallel to the rock or even concentric for pegmatite lenses. Crystal growth rates in pegmatite must be slow to allow gigantic crystals to grow within the confines and pressures of the Earths crust. The mineralogy of a pegmatite is in most cases dominated by some form of feldspar, often with mica and usually with quartz and this is because of the difficulty in counting and sampling mineral grains in a rock which may have crystals from centimeters to meters across. Garnet, commonly almandine or spessartine, is a common mineral within pegmatites intruding mafic, pegmatites associated with granitic domes within the Archaean Yilgarn Craton intruding ultramafic and mafic rocks contain red, orange and brown almandine garnet. Syenite pegmatites are quartz depleted and contain large feldspathoid crystals instead, Pegmatite is difficult to sample representatively due to the large size of the constituent mineral crystals. Often, bulk samples of some 50–60 kg of rock must be crushed to obtain a meaningful, hence, pegmatite is often characterised by sampling the individual minerals which comprise the pegmatite, and comparisons are made according to mineral chemistry. Occasionally, enrichment in the trace elements will result in crystallisation of equally unusual and rare minerals such as beryl, tourmaline, columbite, tantalite, zinnwaldite. Pegmatites are the source of lithium either as spodumene, lithiophyllite or usually from lepidolite. The primary source for caesium is pollucite, a mineral from a zoned pegmatite, the majority of the worlds beryllium is sourced from non-gem quality beryl within pegmatite. Tantalum, niobium, rare-earth elements are sourced from a few pegmatites worldwide, bismuth, molybdenum and tin have been won from pegmatite, but this is not yet an important source of these metals
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This article incorporates public domain material from the United States Geological Survey document: "Mica".
