Nahcolite is a soft, colourless or white carbonate mineral with the composition of sodium bicarbonate called thermokalite. It crystallizes in the monoclinic system. Nahcolite was first described in 1928 for an occurrence in a lava tunnel at Italy, its name refers to the elements which compose it: Na, H, C, O. It occurs as a hot saline lake precipitate or efflorescence, it occurs in association with trona, thenardite, gaylussite, burkeite and borax. It has been reported in a Roman conduit at Campi Flegrei, near Naples.
Clay minerals are hydrous aluminium phyllosilicates, sometimes with variable amounts of iron, alkali metals, alkaline earths, other cations found on or near some planetary surfaces. Clay minerals form in the presence of water and have been important to life, many theories of abiogenesis involve them, they are important constituents of soils, have been useful to humans since ancient times in agriculture and manufacturing. Clays form flat hexagonal sheets similar to the micas. Clay minerals are common weathering products and low-temperature hydrothermal alteration products. Clay minerals are common in soils, in fine-grained sedimentary rocks such as shale and siltstone and in fine-grained metamorphic slate and phyllite. Clay minerals are ultrafine-grained and so may require special analytical techniques for their identification and study; these include x-ray diffraction, electron diffraction methods, various spectroscopic methods such as Mössbauer spectroscopy, infrared spectroscopy, Raman spectroscopy, SEM-EDS or automated mineralogy processes.
These methods can be augmented by polarized light microscopy, a traditional technique establishing fundamental occurrences or petrologic relationships. Given the requirement of water, clay minerals are rare in the Solar System, though they occur extensively on Earth where water has interacted with other minerals and organic matter. Clay minerals have been detected at several locations on Mars, including Echus Chasma, Mawrth Vallis, the Memnonia quadrangle and the Elysium quadrangle. Spectrography has confirmed their presence on asteroids including the dwarf planet Ceres and Tempel 1 as well as Jupiter's moon Europa. Clay minerals can be classified as 1:1 or 2:1, this originates because they are fundamentally built of tetrahedral silicate sheets and octahedral hydroxide sheets, as described in the structure section below. A 1:1 clay would consist of one tetrahedral sheet and one octahedral sheet, examples would be kaolinite and serpentine. A 2:1 clay consists of an octahedral sheet sandwiched between two tetrahedral sheets, examples are talc and montmorillonite.
Clay minerals include the following groups: Kaolin group which includes the minerals kaolinite, dickite and nacrite. Some sources include the kaolinite-serpentine group due to structural similarities. Smectite group which includes dioctahedral smectites such as montmorillonite and beidellite and trioctahedral smectites for example saponite. In 2013, analytical tests by the Curiosity rover found results consistent with the presence of smectite clay minerals on the planet Mars. Illite group which includes the clay-micas. Illite is the only common mineral. Chlorite group includes a wide variety of similar minerals with considerable chemical variation. Other 2:1 clay types exist such as sepiolite or attapulgite, clays with long water channels internal to their structure. Mixed layer clay variations exist for most of the above groups. Ordering is described as random or regular ordering, is further described by the term reichweite, German for range or reach. Literature articles will refer to a R1 ordered illite-smectite, for example.
This type would be ordered in an ISISIS fashion. R0 on the other hand describes random ordering, other advanced ordering types are found. Mixed layer clay minerals which are perfect R1 types get their own names. R1 ordered chlorite-smectite is known as corrensite, R1 illite-smectite is rectorite. Knowledge of the nature of clay became better understood in the 1930s with advancements in x-ray diffraction technology necessary to analyze the molecular nature of clay particles. Standardization in terminology arose during this period as well with special attention given to similar words that resulted in confusion such as sheet and plane. Like all phyllosilicates, clay minerals are characterised by two-dimensional sheets of corner sharing SiO4 tetrahedra and/or AlO4 octahedra; the sheet units have the chemical composition 3O4. Each silica tetrahedron shares 3 of its vertex oxygen atoms with other tetrahedra forming a hexagonal array in two-dimensions; the fourth vertex is not shared with another tetrahedron and all of the tetrahedra "point" in the same direction.
In clays, the tetrahedral sheets are always bonded to octahedral sheets formed from small cations, such as aluminium or magnesium, coordinated by six oxygen atoms. The unshared vertex from the tetrahedral sheet forms part of one side of the octahedral sheet, but an additional oxygen atom is located above the gap in the tetrahedral sheet at the center of the six tetrahedra; this oxygen atom is bonded to a hydrogen atom forming an OH group in the clay structure. Clays can be categorized depending on the way that tetrahedral and octahedral sheets are packaged into layers. If there is only one tetrahedral and one octahedral group in each layer the clay is known as a 1:1 clay; the alternative, known as a 2:1 clay, has two tetrahedral sheets with the unshared vertex of each sheet pointing towards each other and forming each side of the octahedral sheet. Bonding between the tetrahedral and octahedral sheets requires that the tetrahedral sheet becomes corrugated or twisted, causing ditrigonal distortion to the hexagonal array, the octahedral sheet is flattened.
This minimizes the overall bond-valence distortions of the crystallite. Depending on the composition of the tetrahedral and octahedral sheets, the layer will have no charge, or will have a net negative charge. If the layers are charged this charge
Aphthitalite is a potassium sulfate mineral with the chemical formula: 3Na2. It was first described in 1835 for an occurrence on Italy; the name is from the Greek άφθητος, "unalterable", άλας, "salt", for its stability in air. It occurs as fumarolic incrustations in volcanic environments, as small crystals and masses in evaporite deposits and in guano deposits, it occurs associated with thenardite, jarosite and hematite in fumaroles.
Borax known as sodium borate, sodium tetraborate, or disodium tetraborate, is an important boron compound, a mineral, a salt of boric acid. Powdered borax is white, consisting of soft colorless crystals that dissolve in water. A number of related minerals or chemical compounds that differ in their crystal water content are referred to as borax, but the word is used to refer to the octahydrate. Commercially sold borax is dehydrated. Borax is a component of many detergents and enamel glazes, it is used to make buffer solutions in biochemistry, as a fire retardant, as an anti-fungal compound, in the manufacture of fiberglass, as a flux in metallurgy, neutron-capture shields for radioactive sources, a texturing agent in cooking, as a precursor for other boron compounds, along with its inverse, boric acid, is useful as an insecticide. In artisanal gold mining, borax is sometimes used as part of a process meant to eliminate the need for toxic mercury in the gold extraction process, although it cannot directly replace mercury.
Borax was used by gold miners in parts of the Philippines in the 1900s. Borax was first discovered in dry lake beds in Tibet and was imported via the Silk Road to the Arabian Peninsula in the 8th century AD. Borax first came into common use in the late 19th century when Francis Marion Smith's Pacific Coast Borax Company began to market and popularize a large variety of applications under the 20 Mule Team Borax trademark, named for the method by which borax was hauled out of the California and Nevada deserts; the term borax is used for a number of related minerals or chemical compounds that differ in their crystal water content: anhydrous sodium tetraborate, Na2B4O7 sodium tetraborate pentahydrate, Na2B4O7·5H2O sodium tetraborate decahydrate, Na2B4O7·10H2O or equivalently the octahydrate, Na2B4O54·8H2OFrom the chemical perspective, borax contains the 2− ion. In this structure, there are two four-coordinate boron centers and two three-coordinate boron centers. Borax is easily converted to boric acid and other borates, which have many applications.
Its reaction with hydrochloric acid to form boric acid is: Na2B4O7·10H2O + 2 HCl → 4 B3 + 2 NaCl + 5 H2OThe "decahydrate" is sufficiently stable to find use as a primary standard for acid base titrimetry. When borax is added to a flame, it produces a yellow green color. Borax is not used for this purpose in fireworks due to the overwhelming yellow color of sodium. Boric acid is used to color methanol flames a transparent green. Borax is soluble in ethylene glycol, moderately soluble in diethylene glycol and methanol soluble in acetone, it is poorly soluble in cold water, but its solubility increases with temperature. The English word borax is Latinized: the Middle English form was boras, from Old French boras, bourras; that may have been from medieval Latin baurach, borax, along with Spanish borrax and Italian borrace, in the 9th century. Another name for borax is tincal, from Sanskrit; the word tincal "tinkle", or tincar "tinker", refers to crude borax, before it is purified, as mined from lake deposits in Tibet and other parts of Asia.
The word was adopted in the 17th century from Malay tingkal and from Urdu/Persian/Arabic تنکار tinkār/tankār. These all appear to be related to the Sanskrit टांकण ṭānkaṇa. Borax occurs in evaporite deposits produced by the repeated evaporation of seasonal lakes; the most commercially important deposits are found in: Turkey. Borax has been found at many other locations in the Southwestern United States, the Atacama desert in Chile, newly discovered deposits in Bolivia, in Tibet and Romania. Borax can be produced synthetically from other boron compounds. Occurring borax is refined by a process of recrystallization. Borax is used in various household laundry and cleaning products, including the "20 Mule Team Borax" laundry booster, "Boraxo" powdered hand soap, some tooth bleaching formulas. Borate ions are used in biochemical and chemical laboratories to make buffers, e.g. for polyacrylamide gel electrophoresis of DNA and RNA, such as TBE buffer or the newer SB buffer or BBS buffer in coating procedures.
Borate buffers are used as preferential equilibration solution in dimethyl pimelimidate based crosslinking reactions. Borax as a source of borate has been used to take advantage of the co-complexing ability of borate with other agents in water to form complex ions with various substances. Borate and a suitable polymer bed are used to chromatograph non-glycosylated hemoglobin differentially from glycosylated hemoglobin, an indicator of long term hyperglycemia in diabetes mellitus. Borax alone does not have a high affinity for the hardness cations, although it has been used for water-softening, its chemical equation for water-softening is given below: Ca2+ + Na2B4O7 → CaB4O7 ↓ + 2 Na+ Mg2+ + Na2B4O7 → MgB4O7 ↓ + 2 Na+ The sodium ions introduced do not make water ‘hard’. This method is suitable for removing both permanent types of hardness. A mixture of borax and ammonium chloride is used as a flux when welding steel, it lowers the melting point of the unwanted iron oxide. Borax is used mixed with water as a flux when soldering jewelry metals such as gold or silver, where it allows the molten solder to wet the metal and flow evenly int
Mono Lake is a large, shallow saline soda lake in Mono County, formed at least 760,000 years ago as a terminal lake in an endorheic basin. The lack of an outlet causes high levels of salts to accumulate in the lake; these salts make the lake water alkaline. This desert lake has an unusually productive ecosystem based on brine shrimp that thrive in its waters, provides critical habitat for two million annual migratory birds that feed on the shrimp and alkali flies; the native Kutzadika'a people derived nutrition from the Ephydra hians pupae, which live in the shallow waters around the edge of the lake. When the city of Los Angeles diverted water from the freshwater streams flowing into the lake, it lowered the lake level, which imperiled the migratory birds; the Mono Lake Committee formed in response and won a legal battle that forced Los Angeles to replenish the lake level. Mono Lake occupies part of an endorheic basin that has no outlet to the ocean. Dissolved salts in the runoff thus remain in the lake and raise the water's pH levels and salt concentration.
The tributaries of Mono Lake include Lee Vining Creek, Rush Creek and Mill Creek which flows through Lundy Canyon. The basin was formed by geological forces over the last five million years: basin and range crustal stretching and associated volcanism and faulting at the base of the Sierra Nevada. Five million years ago, the Sierra Nevada was an eroded set of rolling hills and Mono Basin and Owens Valley did not yet exist. From 4.5 to 2.6 million years ago, large volumes of basalt were extruded around what is now Cowtrack Mountain. Volcanism in the area occurred 3.8 million to 250,000 years ago. This activity was northwest of Mono Basin and included the formation of Aurora Crater, Beauty Peak, Cedar Hill, Mount Hicks. Mono Lake is believed to have formed at least 760,000 years ago, dating back to the Long Valley eruption. Sediments located below the ash layer hint that Mono Lake could be a remnant of a larger and older lake that once covered a large part of Nevada and Utah, which would put it among the oldest lakes in North America.
At its height during the most recent ice age, the lake would have been about 900 feet deep. Prominent old shore lines, called strandlines by geologists, can be seen west of the Lake. Mono Lake is in a geologically active area at the north end of the Mono–Inyo Craters volcanic chain and is close to Long Valley Caldera. Volcanic activity continues in the Mono Lake vicinity: the most recent eruption occurred 350 years ago, resulting in the formation of Paoha Island. Panum Crater is an excellent example of a combined rhyolite cinder cone. Among the most iconic features of Mono Lake are the columns of limestone that tower over the water surface; these limestone towers consist of calcium carbonate minerals such as calcite. This type of limestone rock is referred to as tufa, a term used for limestone that forms in low to moderate temperatures. Mono Lake is a alkaline lake, or soda lake. Alkalinity is a measure of how many bases are in a solution, how well the solution can neutralize acids. Carbonate and bicarbonate are both bases.
Hence, Mono Lake has a high content of dissolved inorganic carbon. Through supply of calcium ions, the water will precipitate carbonate-minerals such as calcite. Subsurface waters enter the bottom of Mono Lake through small springs. High concentrations of dissolved calcium ions in these subsurface waters cause huge amounts of calcite to precipitate around the spring orifices; the tufa formed at the bottom of the lake. It took many decades or centuries to form the well-recognized tufa towers; when lake levels fell, the tufa towers came to rise above the water surface and stand as the majestic pillars seen today. Description of the Mono Lake tufa dates back to the 1880s, when Edward S. Dana and Israel C. Russell made the first systematic descriptions of the Mono Lake tufa; the tufa occurs as "modern" tufa towers. However, you can find tufa sections from old shorelines, when the lake levels were higher; these pioneering works in tufa morphology are still referred to by researchers today and were confirmed by James R. Dunn in 1953.
The tufa types can be divided into three main categories based on morphology:Lithoid tufa - massive and porous with a rock-like appearance Dendritic tufa - branching structures that look similar to small shrubs Thinolitic tufa - large well-formed crystals of several centimetersThese tufa types vary interchangeably both between individual tufa towers but within individual tufa towers. There can be multiple transitions between tufa morphologies within a single tufa tower. Through time, many hypotheses were developed regarding the formation of the large thinolite crystals in thinolitic tufa, it was clear that the thinolites represented a calcite pseudomorph after some unknown original crystal. However, the original crystal was only determined when the mineral ikaite was discovered in 1963. Ikaite, or hexahydrated CaCO3, is only crystallizes at near-freezing temperatures, it is believed that calcite crystallization inhibitors such as phosphate and organic carbon may aid in the stabilization of ikaite.
When heated, ikaite becomes replaced by smaller crystals of calcite. In the Ikka Fjord of Greenland, ikaite was observed to grow in columns similar to the tufa towers of Mono Lake; this has led scienti
Transparency and translucency
In the field of optics, transparency is the physical property of allowing light to pass through the material without being scattered. On a macroscopic scale, the photons can be said to follow Snell's Law. Translucency is a superset of transparency: it allows light to pass through, but does not follow Snell's law. In other words, a translucent medium allows the transport of light while a transparent medium not only allows the transport of light but allows for image formation. Transparent materials appear clear, with the overall appearance of one color, or any combination leading up to a brilliant spectrum of every color; the opposite property of translucency is opacity. When light encounters a material, it can interact with it in several different ways; these interactions depend on the nature of the material. Photons interact with an object by some combination of reflection and transmission; some materials, such as plate glass and clean water, transmit much of the light that falls on them and reflect little of it.
Many liquids and aqueous solutions are transparent. Absence of structural defects and molecular structure of most liquids are responsible for excellent optical transmission. Materials which do not transmit light are called opaque. Many such substances have a chemical composition which includes what are referred to as absorption centers. Many substances are selective in their absorption of white light frequencies, they absorb certain portions of the visible spectrum while reflecting others. The frequencies of the spectrum which are not absorbed are either reflected or transmitted for our physical observation; this is. The attenuation of light of all frequencies and wavelengths is due to the combined mechanisms of absorption and scattering. Transparency can provide perfect camouflage for animals able to achieve it; this is easier in turbid seawater than in good illumination. Many marine animals such as jellyfish are transparent. With regard to the absorption of light, primary material considerations include: At the electronic level, absorption in the ultraviolet and visible portions of the spectrum depends on whether the electron orbitals are spaced such that they can absorb a quantum of light of a specific frequency, does not violate selection rules.
For example, in most glasses, electrons have no available energy levels above them in range of that associated with visible light, or if they do, they violate selection rules, meaning there is no appreciable absorption in pure glasses, making them ideal transparent materials for windows in buildings. At the atomic or molecular level, physical absorption in the infrared portion of the spectrum depends on the frequencies of atomic or molecular vibrations or chemical bonds, on selection rules. Nitrogen and oxygen are not greenhouse gases because there is no absorption, but because there is no molecular dipole moment. With regard to the scattering of light, the most critical factor is the length scale of any or all of these structural features relative to the wavelength of the light being scattered. Primary material considerations include: Crystalline structure: whether or not the atoms or molecules exhibit the'long-range order' evidenced in crystalline solids. Glassy structure: scattering centers include fluctuations in density or composition.
Microstructure: scattering centers include internal surfaces such as grain boundaries, crystallographic defects and microscopic pores. Organic materials: scattering centers include fiber and cell structures and boundaries. Diffuse reflection - Generally, when light strikes the surface of a solid material, it bounces off in all directions due to multiple reflections by the microscopic irregularities inside the material, by its surface, if it is rough. Diffuse reflection is characterized by omni-directional reflection angles. Most of the objects visible to the naked eye are identified via diffuse reflection. Another term used for this type of reflection is "light scattering". Light scattering from the surfaces of objects is our primary mechanism of physical observation. Light scattering in liquids and solids depends on the wavelength of the light being scattered. Limits to spatial scales of visibility therefore arise, depending on the frequency of the light wave and the physical dimension of the scattering center.
Visible light has a wavelength scale on the order of a half a micrometer. Scattering centers as small. Optical transparency in polycrystalline materials is limited by the amount of light, scattered by their microstructural features. Light scattering depends on the wavelength of the light. Limits to spatial scales of visibility therefore arise, depending on the frequency of the light wave and the physical dimension of the scattering center. For example, since visible light has a wavelength scale on the order of a micrometer, scattering centers will have dimensions on a similar spatial scale. Primary scattering centers in polycrystalline materi
Death Valley is a desert valley located in Eastern California, in the northern Mojave Desert bordering the Great Basin Desert. It is one of the hottest places in the world along with deserts in the Middle East. Death Valley's Badwater Basin is the point of the lowest elevation in North America, at 282 feet below sea level; this point is 84.6 miles east-southeast of Mount Whitney, the highest point in the contiguous United States, with an elevation of 14,505 feet. On the afternoon of July 10, 1913, the United States Weather Bureau recorded a high temperature of 134 °F at Furnace Creek in Death Valley; this temperature stands as the highest ambient air temperature recorded at the surface of the Earth. Located near the border of California and Nevada, in the Great Basin, east of the Sierra Nevada mountains, Death Valley constitutes much of Death Valley National Park and is the principal feature of the Mojave and Colorado Deserts Biosphere Reserve, it is located in Inyo County, California. It runs from north to south between the Amargosa Range on the east and the Panamint Range on the west.
It has an area of about 3,000 sq mi. The highest point in Death Valley itself is Telescope Peak in the Panamint Range, which has an elevation of 11,043 feet. Death Valley is an excellent example of a graben, or a downdropped block of land between two mountain ranges, it lies at the southern end of a geological trough known as Walker Lane. The valley is bisected by a right lateral strike slip fault system, represented by the Death Valley Fault and the Furnace Creek Fault; the eastern end of the left lateral Garlock Fault intersects the Death Valley Fault. Furnace Creek and the Amargosa River flow through the valley but disappear into the sands of the valley floor. Death Valley contains salt pans. According to current geological consensus, at various times during the middle of the Pleistocene era, which ended 10,000–12,000 years ago, an inland lake referred to as Lake Manly formed in Death Valley. Lake Manly was nearly 100 miles long and 600 feet deep, the end-basin in a chain of lakes that began with Mono Lake in the north and continued through multiple basins down the Owens River Valley through Searles and China Lakes and the Panamint Valley to the immediate west.
As the area turned to desert, the water evaporated, leaving the abundance of evaporitic salts such as common sodium salts and borax, which were exploited during the modern history of the region 1883 to 1907. Death Valley has a subtropical, hot desert climate, with long hot summers and short, mild winters, as well as little rainfall; as a general rule, lower altitudes tend to have higher temperatures. When the sun heats the ground, that heat is radiated upward, but the dense below-sea-level air absorbs some of this radiation and radiates some of it back towards the ground. In addition, the high valley walls trap rising hot air and recycle it back down to the valley floor, where it is heated by compression; this process is important in Death Valley, as it provides its specific climate and geography. The valley is surrounded by mountains, while its surface is flat and devoid of plants, so much of the sun's heat can reach the ground, absorbed by soil and rock; when air at ground level is heated, it begins to rise, moving up past steep, high mountain ranges, which cools sinking back down towards the valley more compressed.
This air is reheated by the sun to a higher temperature, moving up the mountain again, whereby the air moves up and down in a circular motion in cycles, similar to how a convection oven works. This heated air increases ground temperature markedly, forming the hot wind currents that are trapped by atmospheric pressure and mountains and thus stay within the valley; such hot wind currents contribute to perpetual drought-like conditions in Death Valley and prevent much cloud formation from passing through the confines of the valley, where precipitation is in the form of a virga. Death Valley holds temperature records because it has an unusually high number of factors that lead to high atmospheric temperatures; the depth and shape of Death Valley influence its summer temperatures. The valley is a long, narrow basin 282 feet below sea level, yet is walled by high, steep mountain ranges; the clear, dry air and sparse plant cover allow sunlight to heat the desert surface. Summer nights provide little relief.
Moving masses of super-heated air blow through the valley creating high temperatures. The hottest air temperature recorded in Death Valley was 134 °F on July 10, 1913, at Greenland Ranch, the highest atmospheric temperature recorded on earth. A report of a temperature of 58 °C recorded in Libya in 1922 was determined to be inaccurate. During the heat wave that peaked with that record, five consecutive days reached 129 above; some meteorologists dispute the accuracy of the 1913 temperature measurement. The highest surface temperature recorded in Death Valley was 201.0 °F on July 15, 1972, at Furnace Creek, the highest ground surface temperature recorded on earth, as well as the only recorded surface temperature of above 200 °F. The greatest number of consecutive days with a maximum temperature of 100 °F or above was 154 days in the summer of 2001; the summer of 1996 had 40 days over 120 °F, 105 days over 110 °F. The summer of 1917 had 52 days where the temperature