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Titanite, or sphene (from the Greek sphenos (σφηνώ), meaning wedge), is a calcium titanium nesosilicate mineral, CaTiSiO5. Trace impurities of iron and aluminium are typically present. Also commonly present are rare earth metals including cerium and yttrium; calcium may be partly replaced by thorium.
Anorthite is the calcium endmember of the plagioclase feldspar mineral series. The chemical formula of pure anorthite is CaAl2Si2O8. Anorthite is found in mafic igneous rocks. Anorthite is rare on the Earth but abundant on the Moon.
Augite is a common rock-forming pyroxene mineral with formula (Ca,Na)(Mg,Fe,Al,Ti)(Si,Al)2O6. The crystals are monoclinic and prismatic. Augite has two prominent cleavages, meeting at angles near 90 degrees.
Smoky quartz is a brownish grey, translucent variety of quartz that ranges in clarity from almost complete transparency to an almost-opaque brownish-gray or black crystals. The color of smoky quartz is produced when natural radiation, emitted from the surrounding rock, activates color centers around aluminum impurities within the crystalline quartz.
Sylvite, or sylvine, is potassium chloride (KCl) in natural mineral form. It forms crystals in the isometric system very similar to normal rock salt, halite (NaCl). The two are, in fact, isomorphous. Sylvite is colorless to white with shades of yellow and red due to inclusions. It has a Mohs hardness of 2.5 and a specific gravity of 1.99. It has a refractive index of 1.4903. Sylvite has a salty taste with a distinct bitterness.
Wollastonite is a calcium inosilicate mineral (CaSiO3) that may contain small amounts of iron, magnesium, and manganese substituting for calcium. It is usually white. It forms when impure limestone or dolomite is subjected to high temperature and pressure, which sometimes occurs in the presence of silica-bearing fluids as in skarns or in contact with metamorphic rocks. Associated minerals include garnets, vesuvianite, diopside, tremolite, epidote, plagioclase feldspar, pyroxene and calcite. It is named after the English chemist and mineralogist William Hyde Wollaston (1766–1828).
Forsterite (Mg2SiO4; commonly abbreviated as Fo; also known as white olivine) is the magnesium-rich end-member of the olivine solid solution series. It is isomorphous with the iron-rich end-member, fayalite. Forsterite crystallizes in the orthorhombic system (space group Pbnm) with cell parameters a 4.75 Å (0.475 nm), b 10.20 Å (1.020 nm) and c 5.98 Å (0.598 nm).
Enstatite is a mineral; the magnesium endmember of the pyroxene silicate mineral series enstatite (MgSiO3) – ferrosilite (FeSiO3). The magnesium rich members of the solid solution series are common rock-forming minerals found in igneous and metamorphic rocks. The intermediate composition, (Mg,Fe)SiO
3, has historically been known as hypersthene, although this name has been formally abandoned and replaced by orthopyroxene. When determined petrographically or chemically the composition is given as relative proportions of enstatite (En) and ferrosilite (Fs) (e.g., En80Fs20).
Fayalite is the iron-rich end-member of the olivine solid-solution series. In common with all minerals in the olivine group, fayalite crystallizes in the orthorhombic system with cell parameters a 4.82 Å, b 10.48 Å and c 6.09 Å.
Cummingtonite is a metamorphic amphibole with the chemical composition (Mg,Fe2+
)
2(Mg,Fe2+
)
5Si
8O
22(OH)
2, magnesium iron silicate hydroxide.
Humite is a mineral found in the volcanically ejected masses of Vesuvius. It was first described in 1813 and named for Abraham Hume (1749–1838).
Trevorite is a rare nickel iron oxide mineral belonging to the spinel group. It has the chemical formula NiFe3+2O4. It is a black mineral with the typical spinel properties of crystallising in the cubic system, black streaked, infusible and insoluble in most acids.
Monticellite and kirschsteinite (commonly also spelled kirschteinite ) are gray silicate minerals of the olivine group with compositions CaMgSiO4 and CaFeSiO4, respectively. Most monticellites have the pure magnesium end-member composition but rare ferroan monticellites and magnesio-kirschsteinite are found with between 30 and 75 mol.% of the iron end member. Pure kirschsteinite is only found in synthetic systems. Monticellite is named after Teodoro Monticelli Italian mineralogist (1759–1845). Kirschsteinite is named after Egon Kirschstein, German geologist.
Zussmanite is a hydrated iron-rich silicate mineral with the chemical formula K(Fe2+,Mg,Mn)13[AlSi17O42](OH)14. It occurs as pale green crystals with perfect cleavage.
William Alexander (Alex) Deer FRS was a distinguished British geologist, petrologist and mineralogist.
Annite is a phyllosilicate mineral in the mica family. It has a chemical formula of KFe32+AlSi3O10(OH)2. Annite is the iron end member of the biotite mica group, the iron rich analogue of magnesium rich phlogopite. Annite is monoclinic and contains tabular crystals and cleavage fragments with pseudohexagonal outlines. There are contact twins with composition surface {001} and twin axis {310}.
Georgius Agricola is considered the 'father of mineralogy'. Nicolas Steno founded the stratigraphy, the geology characterizes the rocks in each layer and the mineralogy characterizes the minerals in each rock. The chemical elements were discovered in identified minerals and with the help of the identified elements the mineral crystal structure could be described. One milestone was the discovery of the geometrical law of crystallization by René Just Haüy, a further development of the work by Nicolas Steno and Jean-Baptiste L. Romé de l'Isle. Important contributions came from some Saxon "Bergraths"/ Freiberg Mining Academy: Johann F. Henckel, Abraham Gottlob Werner and his students. Other milestones were the notion that metals are elements too and the periodic table of the elements by Dmitri Ivanovich Mendeleev. The overview of the organic bonds by Kekulé was necessary to understand the silicates, first refinements described by Bragg and Machatschki; and it was only possibly to understand a crystal structure with Dalton's atomic theory, the notion of atomic orbital and Goldschmidt's explanations. Specific gravity, streak and X-ray powder diffraction are quite specific for a Nickel-Strunz identifier. Nowadays, non-destructive electron microprobe analysis is used to get the empirical formula of a mineral. Finally, the International Zeolite Association (IZA) took care of the zeolite frameworks.
Robert Andrew Howie was a notable English petrologist.
Blairmorite is a very rare porphyritic volcanic rock named after the community of Blairmore in southwestern Alberta, Canada. It is characterized by dominant analcime phenocrysts in a matrix of analcime, sanidine and alkalic pyroxene with accessory titanite, melanite and nepheline. It is a leucocratic variety of analcimite. Blairmorite has also been described as an analcime-rich variety of phonolite.
Johannsenite is a silicate mineral that is a member of the pyroxene family. The mineral can be produced in limestone or due a metamorphic process. The mineral is also associated with Pb-Zn mineralization.
References
- ↑ "Introduction to the Rock-Forming Minerals". Mineralogical Society. Retrieved June 11, 2014.
- ↑ Greenwood, Hugh (1967). "Review of An Introduction to the Rock-Forming Minerals". American Scientist . 55 (1): 113A. JSTOR 27836775.