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Chondrodite
Chondrodite is a nesosilicate mineral with formula . Although it is a fairly rare mineral, it is the most frequently encountered member of the humite group of minerals. It is formed in hydrothermal deposits from locally metamorphosed dolomite. It is also found associated with skarn and serpentinite. It was discovered in 1817 at Pargas in Finland, and named from the Greek for "granule", which is a common habit for this mineral. Formula is the end member formula as given by the International Mineralogical Association, molar mass 351.6 g. There is usually some OH in the F sites, however, and Fe and Ti can substitute for Mg, so the formula for the naturally occurring mineral is better written .Gaines et al (1997) Dana's New Mineralogy Eighth Edition, Wiley Structure The chondrodite structure is based on a slightly distorted hexagonal close packed array of anions O, OH and F with metal ions in the octahedral sites resulting in zigzag chains of octahedra. Chains are staggered ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chondrodite With Magnetite And Silicate Basic Magnesium Fluosilicate Tilly Foster Mine, Brewster, Putnam County, New York 2659
Chondrodite is a Silicate minerals, nesosilicate mineral with formula . Although it is a fairly rare mineral, it is the most frequently encountered member of the Humite (mineral group), humite group of minerals. It is formed in hydrothermal deposits from locally metamorphosed Dolomite (rock), dolomite. It is also found associated with skarn and serpentinite. It was discovered in 1817 at Pargas in Finland, and named from the Greek for "granule", which is a common habit for this mineral. Formula is the end member formula as given by the International Mineralogical Association, molar mass 351.6 g. There is usually some OH in the F sites, however, and Fe and Ti can substitute for Mg, so the formula for the naturally occurring mineral is better written .Gaines et al (1997) Dana's New Mineralogy Eighth Edition, Wiley Structure The chondrodite structure is based on a slightly distorted hexagonal close packed array of anions O, OH and F with metal ions in the octahedral sites result ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Humite (mineral Group)
The humite groupGaines et al (1997) Dana's New Mineralogy Eighth Edition, Wiley is a group of nesosilicates with the general formula . When A is predominantly magnesium we have the humite subgroup: *norbergite, *chondrodite, *humite, *clinohumite, The manganese-humite subgroup has members *alleghanyite, * manganhumite, *sonolite, and the leucophoenicite subgroup has members * ribbeite, * leucophoenicite, *jerrygibbsite Chondrodite is the most common member of the humite group. It may contain Ti up to 9.6% . Chondrodite from Sterling Hill Mine and Franklin Mine contains zinc to 11.5% ZnO and Mn to 36% MnO, and grades to alleghanyite. The humite minerals commonly alter to serpentine or Mg-rich chlorite and dissolve by weathering, leaving iron oxide Iron oxides are chemical compounds composed of iron and oxygen. Several iron oxides are recognized. All are black magnetic solids. Often they are non-stoichiometric. Oxyhydroxides are a related class of compoun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silicate Minerals
Silicate minerals are rock-forming minerals made up of silicate groups. They are the largest and most important class of minerals and make up approximately 90 percent of Earth's crust. In mineralogy, silica (silicon dioxide, ) is usually considered a silicate mineral. Silica is found in nature as the mineral quartz, and its polymorphs. On Earth, a wide variety of silicate minerals occur in an even wider range of combinations as a result of the processes that have been forming and re-working the crust for billions of years. These processes include partial melting, crystallization, fractionation, metamorphism, weathering, and diagenesis. Living organisms also contribute to this geologic cycle. For example, a type of plankton known as diatoms construct their exoskeletons ("frustules") from silica extracted from seawater. The frustules of dead diatoms are a major constituent of deep ocean sediment, and of diatomaceous earth. General structure A silicate mineral is genera ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clinohumite
Clinohumite is an uncommon member of the humite group, a magnesium silicate according to the chemical formula ( Mg, Fe)9( Si O4)4( F,O H)2. The formula can be thought of as four olivine (Mg2SiO4), plus one brucite (Mg(OH)2). Indeed, the mineral is essentially a hydrated olivine and occurs in altered ultramafic rocks and carbonatites. Most commonly found as tiny indistinct grains, large euhedral clinohumite crystals are sought by collectors and occasionally fashioned into bright, yellow-orange gemstones. Only two sources of gem-quality material are known: the Pamir Mountains of Tajikistan, and the Taymyr region of northern Siberia. It is one of two humite group minerals that have been cut into gems, the other being the much more common chondrodite. Properties A monoclinic mineral, clinohumite is typically a dark to light brownish or orangy yellow, somewhat resembling the hessonite variety of grossular. Clinohumite's crystal habit is usually granular, but may also be prismati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alleghanyite
Alleghanyite is a moderately rare humite mineral with formula Mn5(SiO4)2(OH)2, belonging to the nesosilicates class. In general its occurrences are related with metamorphic (metamorphosed) manganese deposits. The mineral is named after Alleghany County, North Carolina North Carolina () is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. The state is the List of U.S. states and territories by area, 28th largest and List of states and territories of the United ..., US. See also * Jerrygibbsite * Chondrodite * Clinohumite * Humite References Manganese(II) minerals Humite group Monoclinic minerals Minerals in space group 14 {{silicate-mineral-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dolomite (rock)
Dolomite (also known as dolomite rock, dolostone or dolomitic rock) is a sedimentary carbonate rock that contains a high percentage of the mineral dolomite, CaMg(CO3)2. It occurs widely, often in association with limestone and evaporites, though it is less abundant than limestone and rare in Cenozoic rock beds (beds less than about 66 million years in age). The first geologist to distinguish dolomite rock from limestone was Belsazar Hacquet in 1778. Most dolomite was formed as a magnesium replacement of limestone or of lime mud before lithification. The geological process of conversion of calcite to dolomite is known as dolomitization and any intermediate product is known as dolomitic limestone. The "dolomite problem" refers to the vast worldwide depositions of dolomite in the past geologic record in contrast to the limited amounts of dolomite formed in modern times. Recent research has revealed sulfate-reducing bacteria living in anoxic conditions precipitate dolomite which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metamorphism
Metamorphism is the transformation of existing rock (the protolith) to rock with a different mineral composition or texture. Metamorphism takes place at temperatures in excess of , and often also at elevated pressure or in the presence of chemically active fluids, but the rock remains mostly solid during the transformation. Metamorphism is distinct from weathering or diagenesis, which are changes that take place at or just beneath Earth's surface. Various forms of metamorphism exist, including regional, contact, hydrothermal, shock, and dynamic metamorphism. These differ in the characteristic temperatures, pressures, and rate at which they take place and in the extent to which reactive fluids are involved. Metamorphism occurring at increasing pressure and temperature conditions is known as ''prograde metamorphism'', while decreasing temperature and pressure characterize ''retrograde metamorphism''. Metamorphic petrology is the study of metamorphism. Metamorphic petrologis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antigorite
Antigorite is a lamellated, monoclinic mineral in the phylosilicate serpentine subgroup with the ideal chemical formula of (Mg,Fe2+)3Si2O5(OH)4. It is the high-pressure polymorph of serpentine and is commonly found in metamorphosed serpentinites. Antigorite, and its serpentine polymorphs, play an important role in subduction zone dynamics due to their relative weakness and high weight percent of water (up to 13 weight % H2O). It is named after its type locality, the Geisspfad serpentinite, Valle Antigorio in the border region of Italy/ Switzerland and is commonly used as a gemstone in jewelry and carvings. Geologic occurrences Antigorite is found in low-temperature, high-pressure (or high-deformation) environments, including both extensional and compressional tectonic regimes. Serpentines are commonly found in the ultramafic greenschist facies of subduction zones, and are visible on the Earth's surface through secondary exhumation. Serpentinites that contain antigorite are u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetite
Magnetite is a mineral and one of the main iron ores, with the chemical formula Fe2+Fe3+2O4. It is one of the oxides of iron, and is ferrimagnetic; it is attracted to a magnet and can be magnetized to become a permanent magnet itself. With the exception of extremely rare native iron deposits, it is the most magnetic of all the naturally occurring minerals on Earth. Naturally magnetized pieces of magnetite, called lodestone, will attract small pieces of iron, which is how ancient peoples first discovered the property of magnetism. Magnetite is black or brownish-black with a metallic luster, has a Mohs hardness of 5–6 and leaves a black streak. Small grains of magnetite are very common in igneous and metamorphic rocks. The chemical IUPAC name is iron(II,III) oxide and the common chemical name is ''ferrous-ferric oxide''. Properties In addition to igneous rocks, magnetite also occurs in sedimentary rocks, including banded iron formations and in lake and marine sediment ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnesite
Magnesite is a mineral with the chemical formula ( magnesium carbonate). Iron, manganese, cobalt, and nickel may occur as admixtures, but only in small amounts. Occurrence Magnesite occurs as veins in and an alteration product of ultramafic rocks, serpentinite and other magnesium rich rock types in both contact and regional metamorphic terrains. These magnesites are often cryptocrystalline and contain silica in the form of opal or chert. Magnesite is also present within the regolith above ultramafic rocks as a secondary carbonate within soil and subsoil, where it is deposited as a consequence of dissolution of magnesium-bearing minerals by carbon dioxide in groundwaters. Isotopic structure: clumped isotope The recent advancement in the field of stable isotope geochemistry is the study of isotopic structure of minerals and molecules. This requires study of molecules with high resolutions looking at bonding scenario (how heavy isotopes are bonded to each other)- leading to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
West Greenland
Kitaa, originally Vestgrønland ("West Greenland"), is a former administrative division of Greenland. It was by far the most populated of the divisions, being home to almost 90% of the total population. The divisions were de facto replaced by statistical regions after Greenland received home rule in 1979. It is bordered in the west by the Baffin Bay, Davis Strait, Labrador Sea and the North Atlantic Ocean. To the east lies Tunu. All but three of the island territory's municipalities were located in West Greenland. These were (in geographical order, from south to north): * Nanortalik * Qaqortoq * Narsaq * Ivittuut * Paamiut * Nuuk * Maniitsoq * Sisimiut * Kangaatsiaq * Aasiaat * Qasigiannguit * Ilulissat * Qeqertarsuaq * Uummannaq * Upernavik Upernavik (Kalaallisut: "Springtime Place") is a small town in the Avannaata municipality in northwestern Greenland, located on a small island of the same name. With 1,092 inhabitants as of 2020, it is the twelfth-largest town in Green ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
