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Mineralogy is a subject of geology specializing in the scientific study of the chemistry, crystal structure, and physical properties of minerals and mineralized artifacts. Specific studies within mineralogy include the processes of mineral origin and formation, classification of minerals, their geographical distribution, as well as their utilization.
Uraninite, formerly pitchblende, is a radioactive, uranium-rich mineral and ore with a chemical composition that is largely UO2 but because of oxidation typically contains variable proportions of U3O8. Radioactive decay of the uranium causes the mineral to contain oxides of lead and trace amounts of helium. It may also contain thorium and rare-earth elements.
Petalite, also known as castorite, is a lithium aluminum phyllosilicate mineral LiAlSi4O10, crystallizing in the monoclinic system. Petalite occurs as colorless, pink, grey, yellow, yellow grey, to white tabular crystals and columnar masses. It occurs in lithium-bearing pegmatites with spodumene, lepidolite, and tourmaline. Petalite is an important ore of lithium, and is converted to spodumene and quartz by heating to ~500 °C and under 3 kbar of pressure in the presence of a dense hydrous alkali borosilicate fluid with a minor carbonate component. Petalite (and secondary spodumen formed from it) is lower in iron than primary spodumene, making it a more useful source of lithium in, e.g., the production of glass. The colorless varieties are often used as gemstones.
Tridymite is a high-temperature polymorph of silica and usually occurs as minute tabular white or colorless pseudo-hexagonal crystals, or scales, in cavities in felsic volcanic rocks. Its chemical formula is SiO2. Tridymite was first described in 1868 and the type location is in Hidalgo, Mexico. The name is from the Greek tridymos for triplet as tridymite commonly occurs as twinned crystal trillings (compound crystals comprising three twinned crystal components).
Moolooite is a rare blue-green mineral with the formula Cu++(C2O4)·n(H2O) (n<1) (copper oxalate hydrate). It was discovered by Richard M Clarke and Ian R Williams in Bunbury Well, Mooloo Downs station, Murchison, Western Australia in 1986. It has an orthorhombic crystalline structure, and is formed by the interaction of bird guano with weathering copper sulfides. It is used in plastics to color them blueish-green.
Cummingtonite is a metamorphic amphibole with the chemical composition (Mg,Fe2+
)
2(Mg,Fe2+
)
5Si
8O
22(OH)
2, magnesium iron silicate hydroxide.
Stishovite is an extremely hard, dense tetragonal form (polymorph) of silicon dioxide. It is very rare on the Earth's surface; however, it may be a predominant form of silicon dioxide in the Earth, especially in the lower mantle.
Gahnite, ZnAl2O4, is a rare mineral belonging to the spinel group. It forms octahedral crystals which may be green, blue, yellow, brown or grey. It often forms as an alteration product of sphalerite in altered massive sulphide deposits such as at Broken Hill, Australia. Other occurrences include Falun, Sweden where it is found in pegmatites and skarns; and, in the United States, Charlemont, Massachusetts; Spruce Pine, North Carolina; White Picacho district, Arizona; Topsham, Maine; and Franklin, New Jersey.
Painite is a very rare borate mineral. It was first found in Myanmar by British mineralogist and gem dealer Arthur C.D. Pain who misidentified it as ruby, until it was discovered as a new gemstone in the 1950s. When it was confirmed as a new mineral species, the mineral was named after him. Due to its rarity, painite can cost in the range of between US$50,000 to $60,000 per carat.
Hauerite is a manganese sulfide mineral with the chemical formula MnS2. It forms reddish brown or black octahedral crystals with the pyrite structure and it is usually found associated with the sulfides of other transition metals such as rambergite. It occurs in low temperature, sulfur rich environments associated with solfataras and salt deposits in association with native sulfur, realgar, gypsum and calcite.
Weddellite (CaC2O4·2H2O) is a mineral form of calcium oxalate named for occurrences of millimeter-sized crystals found in bottom sediments of the Weddell Sea, off Antarctica. Occasionally, weddellite partially dehydrates to whewellite, forming excellent pseudomorphs of grainy whewellite after weddellite's short tetragonal dipyramids. It was first described in 1936 but only named in 1942.
Triphylite is a lithium iron(II) phosphate mineral with the chemical formula LiFePO4. It is a member of the triphylite group and forms a complete solid solution series with the lithium manganese(II) phosphate, lithiophilite. Triphylite crystallizes in the orthorhombic crystal system. It rarely forms prismatic crystals and is more frequently found in hypidiomorphic rock. It is bluish- to greenish-gray in color, but upon alteration becomes brown to black.
Whewellite is a mineral, hydrated calcium oxalate, formula Ca C2O4·H2O. Because of its organic content it is thought to have an indirect biological origin; this hypothesis is supported by its presence in coal and sedimentary nodules. However, it has also been found in hydrothermal deposits where a biological source appears improbable. For this reason, it may be classed as a true mineral.
Antarcticite is an uncommon calcium chloride hexahydrate mineral with formula CaCl2·6H2O. It forms colorless acicular trigonal crystals. It is hygroscopic and has a low specific gravity of 1.715.
Kampfite is a rare barium silicate–carbonate–halide mineral with the chemical formula Ba12(Si11Al5)O31(CO3)8Cl5. Discovered in 1964 and described in 2001, it is named after Anthony R. Kampf. The mineral is known only from Fresno County, California.
Nambulite is a lithium bearing manganese silicate mineral with the chemical formula (Li,Na)Mn4Si5O14(OH). It is named after the mineralogist, Matsuo Nambu (born 1917) of Tohoko University, Japan, who is known for his research in manganese minerals. The mineral was first discovered in the Funakozawa Mine of northeastern Japan, a metasedimentary manganese ore.
Stellerite is a rare mineral discovered by and named after Georg Wilhelm Steller, a German explorer and zoologist. The mineral has a general formula of Ca[Al2Si7O18]·7H2O. Like most rare minerals, there are few commercial uses for stellerite. Mineral collectors are lucky to find it in good enough crystal form. Zeolites, including stellerite, have been studied using a dehydration process to gauge the potential use of their phases as molecular sieves, sorbents, and catalysts.
Messelite is a mineral with formula Ca2(Fe2+,Mn2+)(PO4)2·2H2O. It was discovered in Germany and described in 1890. The mineral was subsequently discredited in 1940, reinstated and named neomesselite in 1955, and the name restored to messelite in 1959.
An organic mineral is an organic compound in mineral form. An organic compound is any compound containing carbon, aside from some simple ones discovered before 1828. There are three classes of organic mineral: hydrocarbons, salts of organic acids, and miscellaneous. Organic minerals are rare, and tend to have specialized settings such as fossilized cacti and bat guano. Mineralogists have used statistical models to predict that there are more undiscovered organic mineral species than known ones.
Humboldtine is a rarely occurring mineral from the mineral class of "organic compounds" with the chemical composition FeC2O4•2H2O and is therefore a water-containing iron(II) oxalate or the iron salt of oxalic acid.
References
- ↑ Anthony, John W.; Bideaux, Richard A.; Bladh, Kenneth W.; Nichols, Monte C., eds. (27 October 2022). Handbook of Mineralogy. Chantilly, VA 20151-1110 USA: Mineralogical Society of America.
{{cite book}}: CS1 maint: location (link) - 1 2 3 Kampf, Anthony (2020). "Uroxite and metauroxite, the first two uranyl oxalate minerals". Mineralogical Magazine. 84 (1): 131–141. doi:10.1180/mgm.2019.57. S2CID 202886161.