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Kaolinite ( KAY-ə-lə-nyte, -lih-) is a clay mineral, with the chemical composition Al2Si2O5(OH)4. It is an important industrial mineral. It is a layered silicate mineral, with one tetrahedral sheet of silica (SiO4) linked through oxygen atoms to one octahedral sheet of alumina (AlO6) octahedra. Rocks that are rich in kaolinite are known as kaolin or china clay. Kaolin is occasionally referred to by the antiquated term lithomarge, from the Ancient Greek litho- and Latin marga, meaning 'stone of marl'. Presently the name lithomarge can refer to a compacted, massive form of kaolin.
In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.
Spinel is the magnesium/aluminium member of the larger spinel group of minerals. It has the formula MgAl
2O
4 in the cubic crystal system. Its name comes from the Latin word spinella, which means spine in reference to its pointed crystals.
Tantalum is a chemical element with the symbol Ta and atomic number 73. Previously known as tantalium, it is named after Tantalus, a villain from Greek mythology. Tantalum is a rare, hard, blue-gray, lustrous transition metal that is highly corrosion-resistant. It is part of the refractory metals group, which are widely used as minor components in alloys.
Talc, or talcum, is a clay mineral, composed of hydrated magnesium silicate with the chemical formula Mg3Si4O10(OH)2. Talc in powdered form, often combined with corn starch, is used as baby powder. This mineral is used as a thickening agent and lubricant. It is an ingredient in ceramics, paint, and roofing material. It is a main ingredient in many cosmetics. It occurs as foliated to fibrous masses, and in an exceptionally rare crystal form. It has a perfect basal cleavage and an uneven flat fracture, and it is foliated with a two-dimensional platy form.
Garnets are a group of silicate minerals that have been used since the Bronze Age as gemstones and abrasives.
Feldspars are a group of rock-forming aluminium tectosilicate minerals, containing sodium, calcium, potassium, or barium. The most common members of the feldspar group are the plagioclase (sodium-calcium) feldspars and the alkali (potassium-sodium) feldspars. Feldspars make up about 60% of the Earth's crust, and 41% of the Earth's continental crust by weight.
Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate (CaCO3). It is a very common mineral, particularly as a component of limestone. Calcite defines hardness 3 on the Mohs scale of mineral hardness, based on scratch hardness comparison. Large calcite crystals are used in optical equipment, and limestone composed mostly of calcite has numerous uses.
The mineral olivine is a magnesium iron silicate with the chemical formula (Mg2+, Fe2+)2SiO4. It is a type of nesosilicate or orthosilicate. The primary component of the Earth's upper mantle, it is a common mineral in Earth's subsurface, but weathers quickly on the surface. For this reason, olivine has been proposed as a good candidate for accelerated weathering to sequester carbon dioxide from the Earth's oceans and atmosphere, as part of climate change mitigation. Olivine also has many other historical uses, such as the gemstone peridot (or chrysolite), as well as industrial applications like metalworking processes.
Zircon is a mineral belonging to the group of nesosilicates and is a source of the metal zirconium. Its chemical name is zirconium(IV) silicate, and its corresponding chemical formula is ZrSiO4. An empirical formula showing some of the range of substitution in zircon is (Zr1–y, REEy)(SiO4)1–x(OH)4x–y. Zircon precipitates from silicate melts and has relatively high concentrations of high field strength incompatible elements. For example, hafnium is almost always present in quantities ranging from 1 to 4%. The crystal structure of zircon is tetragonal crystal system. The natural color of zircon varies between colorless, yellow-golden, red, brown, blue, and green.
The pyroxenes are a group of important rock-forming inosilicate minerals found in many igneous and metamorphic rocks. Pyroxenes have the general formula XY(Si,Al)2O6, where X represents calcium (Ca), sodium (Na), iron or magnesium (Mg) and more rarely zinc, manganese or lithium, and Y represents ions of smaller size, such as chromium (Cr), aluminium (Al), magnesium (Mg), cobalt (Co), manganese (Mn), scandium (Sc), titanium (Ti), vanadium (V) or even iron or. Although aluminium substitutes extensively for silicon in silicates such as feldspars and amphiboles, the substitution occurs only to a limited extent in most pyroxenes. They share a common structure consisting of single chains of silica tetrahedra. Pyroxenes that crystallize in the monoclinic system are known as clinopyroxenes and those that crystallize in the orthorhombic system are known as orthopyroxenes.
Pyrochlore2Nb2O6(OH,F) is a mineral group of the niobium end member of the pyrochlore supergroup. The general formula, A2B2O7, represent a family of phases isostructural to the mineral pyrochlore. Pyrochlores are an important class of materials in diverse technological applications such as luminescence, ionic conductivity, nuclear waste immobilization, high temperature thermal barrier coatings, automobile exhaust gas control, catalysts, solid oxide fuel cell, ionic/electrical conductors etc.
Ilmenite is a titanium-iron oxide mineral with the idealized formula FeTiO
3. It is a weakly magnetic black or steel-gray solid. Ilmenite is the most important ore of titanium and the main source of titanium dioxide, which is used in paints, printing inks, fabrics, plastics, paper, sunscreen, food and cosmetics.
Titanium dioxide, also known as titanium(IV) oxide or titania, is the inorganic compound with the chemical formula TiO
2. When used as a pigment, it is called titanium white, Pigment White 6 (PW6), or CI 77891. It is a white, water-insoluble solid, although mineral forms can appear black. As a pigment, it has a wide range of applications, including paint, sunscreen, and food coloring. When used as a food coloring, it has E number E171. World production in 2014 exceeded 9 million tonnes. It has been estimated that titanium dioxide is used in two-thirds of all pigments, and pigments based on the oxide have been valued at $13.2 billion.
Cobalt sulfide is the name for chemical compounds with a formula CoxSy. Well-characterized species include minerals with the formula CoS, CoS2, Co3S4, and Co9S8. In general, the sulfides of cobalt are black, semiconducting, insoluble in water, and nonstoichiometric.
Zadovite is an extremely rare mineral with formula BaCa6[(SiO4)(PO4)](PO4)2F. Together with its vanadium-analogue, aradite, zadovite occur in paralavas (type of pyrometamorphic rocks). Both minerals have structures similar to nabimusaite, and these three minerals occur in the Hatrurim Formation of Israel. Structure of all three minerals is related to that of hatrurite. Minerals combining barium, phosphorus and silicon together are scarce.
Nabimusaite is a very rare mineral with formula KCa12(SiO4)4(SO4)2O2F. Its structure, as in case of similar aradite and zadovite, is a derivative of the one of hatrurite. Nabimusaite gives its name to the nabimusaite group. The mineral was found in a pyrometamorphic rock of the Hatrurim Formation, a site known for the natural pyrometamorphism. It is interpreted to have formed due to interaction of a precursor assemblage with sulfate-rich melt. Nabimusaite is potassium- and fluorine-analogue of dargaite.
The sulfate fluorides are double salts that contain both sulfate and fluoride anions. They are in the class of mixed anion compounds. Some of these minerals are deposited in fumaroles.
Fumarole minerals are minerals which are deposited by fumarole exhalations. They form when gases and compounds desublimate or precipitate out of condensates, forming mineral deposits. They are mostly associated with volcanoes, but have been encountered on burning coal deposits as well. They can be black or multicoloured and are often unstable upon exposure to the atmosphere.
References
- ↑
- Gfeller, F., Galuskina, I.O., Galuskin, E.V., Armbruster, T., Vapnik, Y., Dulski, M., Gardocki, M., Jeżak, L., and Murashko, M., 2015. Dargaite, IMA 2015-068. CNMNC Newsletter No. 28, December 2015, 1860; Mineralogical Magazine 79, 1859–1864
- ↑ "Dargaite: Dargaite mineral information and data". Mindat.org. Retrieved 2016-03-02.
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