Chemistry

Ankerite: Properties and Occurrence

Ankerite: Properties and Occurrence

Ankerite is a calcium, iron, magnesium, manganese carbonate mineral of the group of rhombohedral carbonates with the formula: Ca(Fe, Mg, Mn)(CO3)2. It forms in iron-rich hydrothermal veins and metamorphic rocks with sulfides and other iron minerals. In composition, it is closely related to dolom.....

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Anhydrite: Properties and Occurrence

Anhydrite: Properties and Occurrence

Anhydrite is a mineral – anhydrous calcium sulfate, CaSO4. It is not a common mineral, as it easily alters the much more common mineral Gypsum from the addition of water into its chemical structure. Anhydrite receives its name from the Greek “anhydrous” which means “withou.....

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Anglesite: Properties and Occurrence

Anglesite: Properties and Occurrence

Anglesite is a lead sulfate mineral with the chemical formula PbSO4. It is a secondary lead mineral that always forms through the alteration of lead sulfides, primarily Galena. It occurs as an oxidation product of primary lead sulfide ore, Galena. Anglesite occurs as prismatic orthorhombic crysta.....

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Andyrobertsite

Andyrobertsite

Andyrobertsite is a rare, complex arsenate mineral with a blue color. It is found in the Tsumeb mine in Namibia and named after Andrew C. Roberts (b. 1950), a mineralogist with the Geological Survey of Canada. A Ca-rich analog (with Ca instead of Cd) is called calcioandyrobertsite and has a more .....

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Andradite

Andradite

Andradite is a species of the garnet group. It is a nesosilicate, with formula Ca3Fe2Si3O12. It is a member of the Garnet group, and although not as well-known as other Garnets such as Almandine or Pyrope, it is still fairly abundant and can produce fine Garnet gemstones. Andradite includes three.....

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Andesine

Andesine

Andesine is a silicate mineral, a member of the plagioclase feldspar solid solution series. Its chemical formula is (Ca, Na)(Al, Si)4O8, where Ca/(Ca + Na) (% anorthite) is between 30%-50%. It is a red feldspar gemstone, sometimes with greenish hints and a slight labradorescent effect. The plagio.....

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Andersonite: Properties and Occurrence

Andersonite: Properties and Occurrence

Andersonite, Na2Ca (UO2) (CO3)3·6H2O, or hydrated sodium calcium uranyl carbonate. It is a rare uranyl carbonate mineral, that was only described in the last half century and was first described in 1948. Named after Charles Alfred Anderson (1902–1990) of the United States Geological Survey, wh.....

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Andalusite: Properties and Occurrence

Andalusite: Properties and Occurrence

Andalusite is an aluminum nesosilicate mineral with the chemical formula Al2SiO5. It is a polymorph with two other minerals: kyanite and sillimanite. Andalusite is trimorphic with kyanite and sillimanite, being the lower pressure mid temperature polymorph. It is not Radioactive. It is usually onl.....

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Anatase

Anatase

Anatase is one of the three mineral forms of titanium dioxide (TiO2), the other two being brookite and rutile. At higher temperatures, about 915 degrees Celsius, anatase will automatically revert to the rutile structure. It is always found as small, isolated and sharply developed crystals, and li.....

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Ancylite

Ancylite

Ancylite is a group of hydrous strontium carbonates minerals containing cerium, lanthanum and minor amounts of other rare-earth elements. The composition is Sr(Ce, La)(CO3)2(OH)·H2O with ancylite-Ce enriched in cerium and ancylite-La in lanthanum. It is uncommon to a rare mineral that can be fou.....

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Anapaite

Anapaite

Anapaite is a calcium–iron phosphate mineral with formula: Ca2Fe2+ (PO4)2·4H2O. It is rare and beautiful phosphate mineral. It is a mineral that typically occurs in cavities in fossil-bearing sedimentary rocks. It is also found in phosphate bearing iron ores and rarely in pegmatites. It is com.....

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Anandite

Anandite

Anandite is a rare phyllosilicate with formula (Ba, K)(Fe2+, Mg)3(Si, Al, Fe)4O10(S, OH)2. It crystallizes in the monoclinic crystal system. It is black in color with a glassy luster and a near perfect cleavage. It is a rare mineral with important sources only in Sri Lanka and the United States .....

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