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Lamprophyllite
Lamprophyllite (named for its lustrous cleavage) is a rare, but widespread mineral Ti-silicate mineral usually found in intrusive agpasitic igneous rocks. Yellow, reddish brown, Vitreous, Pearly. Lamprophyllite formula is (Sr,Ba,K,Na)2Na(Na,Fe,Mn)2Ti[Ti2O2(Si2O7)2[(O, OH,F)2 . Full isomorphic range between lampropyllite and baritollalpropyllite exist. The general crystal-chemical formula for lampropyllite-related minerals can be written as A2[(M1)(M2)2(M3)X2] 5] L2(Si2O7)2O2], where the contents of the O and H sheets are given in square brackets in this order and A = Sr, Ba,K, Na; M1 = Na, Mn2+; M2 = Na, Mn2+, Fe2+, Ca; M3 = Ti, Mn2+, Mg, Fe3+, Fe2+; L = Ti, Fe3+; X = OH, O, F. Lamprophyllite is monoclinic In crystallography, the monoclinic crystal system is one of the seven crystal systems. A crystal system is described by three vectors. In the monoclinic system, the crystal is described by vectors of unequal lengths, as in the orthorhombic s ..., The mineral also has ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Agpaitic Rock
An agpaitic rock is a peralkaline igneous rock, typically nepheline syenite or phonolite. Characteristic minerals in these rocks include complex silicates containing zirconium, titanium, sodium, calcium, the rare-earth elements, and fluorine. Agpaites are unusually rich in rare and obscure minerals such as eudialyte, wöhlerite, loparite, astrophyllite, lorenzenite, catapleiite, lamprophyllite, and villiaumite (NaF). Sodalite is typically present, but not diagnostic.http://www.minersoc.org/pages/Archive-MM/Volume_39/39-306-729.pdf Edgar, A. D., ''On the use of the term 'Agpaitic'', MINERALOGICAL MAGAZINE, JUNE I974, VOL. 39, PP. 729–30. Less alkaline igneous rocks in which zircon, titanite, and ilmenite are characteristic are called miaskitic. Agpaitic rocks were first described for an occurrence in the Ilimaussaq complex of southwest Greenland in 1911. Agpaitic rocks are present in the Lovozero and Khibiny Massif complexes of the Kola Peninsula, in Mont Saint-Hilaire, Que ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silicate Mineral
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 generally a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Igneous
Igneous rock (derived from the Latin word ''ignis'' meaning fire), or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rock is formed through the cooling and solidification of magma or lava. The magma can be derived from partial melts of existing rocks in either a planet's mantle or crust. Typically, the melting is caused by one or more of three processes: an increase in temperature, a decrease in pressure, or a change in composition. Solidification into rock occurs either below the surface as intrusive rocks or on the surface as extrusive rocks. Igneous rock may form with crystallization to form granular, crystalline rocks, or without crystallization to form natural glasses. Igneous rocks occur in a wide range of geological settings: shields, platforms, orogens, basins, large igneous provinces, extended crust and oceanic crust. Geological significance Igneous and metamorphic rocks make up 90–95% of the to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
