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Melilitite
Melilite refers to a mineral of the melilite group. Minerals of the group are solid solutions of several endmembers, the most important of which are gehlenite and åkermanite. A generalized formula for common melilite is ( Ca, Na)2( Al, Mg, Fe2+) Silicon">Si<_a>[.html" ;"title="Silicon.html" ;"title="Silicon">Si)Silicon">SiOxygen">O7 Discovered in 1793 near Rome, it has a yellowish, greenish-brown color. The name derives from the Greek words meli (μέλι) "honey" and lithos (λίθους) "stone".The name refers to a group of minerals (melilite group) with chemically similar composition, nearly always minerals in åkermanite-gehlenite series. Minerals of the melilite group are sorosilicates. They have the same basic structure, of general formula ''A''2''B(T''2O7). The melilite structure consist of pairs of fused ''T''O4, where ''T'' may be Si, Al, B, in bow-tie form. Sharing one corner, the formula of the pair is ''T''2O7. These bow-ties are linked togeth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Melilite Group
Melilite refers to a mineral of the melilite group. Minerals of the group are solid solutions of several endmembers, the most important of which are gehlenite and åkermanite. A generalized formula for common melilite is ( Ca, Na)2( Al, Mg, Fe2+) Silicon">Si<_a>[.html" ;"title="Silicon.html" ;"title="Silicon">Si)Silicon">SiOxygen">O7 Discovered in 1793 near Rome, it has a yellowish, greenish-brown color. The name derives from the Greek words meli (μέλι) "honey" and lithos (λίθους) "stone".The name refers to a group of minerals (melilite group) with chemically similar composition, nearly always minerals in åkermanite-gehlenite series. Minerals of the melilite group are sorosilicates. They have the same basic structure, of general formula ''A''2''B(T''2O7). The melilite structure consist of pairs of fused ''T''O4, where ''T'' may be Si, Al, B, in bow-tie form. Sharing one corner, the formula of the pair is ''T''2O7. These bow-ties are linked together ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gehlenite
Gehlenite, (Ca2Al lSiO7, is a sorosilicate, Al-rich endmember of the melilite complete solid solution series with akermanite.Deer et al., 1993 The type locality is in the Monzoni Mountains, Fassa Valley in Trentino in Italy, and is named after the Adolf Ferdinand Gehlen (1775–1815) by A.J. Fuchs in 1815.Dana et al. 1997 Geological occurrence Gehlenite is found in carbonaceous chondrites from which it condensed as a refractory mineral in the hotter stages ( FU Ori) of the presolar nebula,Grossman L (1972) Condensation in the primitive solar nebula, Geochemica et Cosmochemica Acta, 36, 597–619 and was subsequently consumed in processes which created enstatite and other more abundant minerals making it a remnant mineral from the early solar nebula (along with corundum and spinel). Its occurrence in the early condensation phase of the solar nebula was predicted by Harry Lord in the 1950s, but studies of carbonaceous chondrites did not support this claim until the Allende mete ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sorosilicate
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, the crystalline forms of silica (silicon dioxide, ) are usually considered to be tectosilicates, and they are classified as such in the Dana system (75.1). However, the Nickel-Strunz system classifies them as oxide minerals (4.DA). 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 seawat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hardystonite
Hardystonite is a rare calcium zinc silicate mineral first described from the Franklin, New Jersey, U.S. zinc deposits. It often contains lead, which was detrimental to the zinc smelting process, so it was not a useful ore mineral. Like many of the famous Franklin minerals, hardystonite responds to short wave ultraviolet (254 nm wavelength) light, emitting a fluorescence from dark purple to bright violet blue. In daylight, it is white to gray to light pink in color, sometimes with a vitreous or greasy luster. It is very rarely found as well formed crystals, and these are usually rectangular in appearance and rock-locked.Dunn, Pete J. Franklin and Sterling Hill, New Jersey: the world's most magnificent mineral deposits. Dr. Pete J. Dunn, 2004. Hardystonite has a chemical composition of Ca2ZnSi2O7. It is frequently found with willemite (fluoresces green), calcite Calcite is a Carbonate minerals, carbonate mineral and the most stable Polymorphism (materials science), p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gugiaite
Gugiaite is a melilite mineral, named for the Chinese village of Gugia where it was first discovered. Its chemical formula is . It occurs mostly in skarns with melanite adjacent to an alkali syenite and has no economic value. Its crystals are small tetragonal tablets with vitreous luster and perfect cleavage. It is colorless and transparent with a density of three. The mineral belongs to space group P21m and is strongly piezoelectric. Shortly after the discovery of gugiaite, it was noted that a new name was unnecessary as it could have been considered an end member of meliphanite, differing mainly in containing much less sodium and fluorine. Recent data have confirmed that gugiaite differs from meliphanite optically and structurally. Gugiaite is a melilite and is distinctly different from other beryllium minerals such as meliphanite and leucophanite. Gugiaite is named for its locality near the village of Gugia, China. Incongruent information exists regarding Gugia; conseq ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iron
Iron is a chemical element; it has symbol Fe () and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, forming much of Earth's outer and inner core. It is the fourth most abundant element in the Earth's crust, being mainly deposited by meteorites in its metallic state. Extracting usable metal from iron ores requires kilns or furnaces capable of reaching , about 500 °C (900 °F) higher than that required to smelt copper. Humans started to master that process in Eurasia during the 2nd millennium BC and the use of iron tools and weapons began to displace copper alloys – in some regions, only around 1200 BC. That event is considered the transition from the Bronze Age to the Iron Age. In the modern world, iron alloys, such as steel, stainless steel, cast iron and special steels, are by far the most common industrial metals, due to their mechan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetragonal
In crystallography, the tetragonal crystal system is one of the 7 crystal systems. Tetragonal crystal lattices result from stretching a cubic lattice along one of its lattice vectors, so that the Cube (geometry), cube becomes a rectangular Prism (geometry), prism with a square base (''a'' by ''a'') and height (''c'', which is different from ''a''). Bravais lattices There are two tetragonal Bravais lattices: the primitive tetragonal and the body-centered tetragonal. The body-centered tetragonal lattice is equivalent to the primitive tetragonal lattice with a smaller unit cell, while the face-centered tetragonal lattice is equivalent to the body-centered tetragonal lattice with a smaller unit cell. Crystal classes The point groups that fall under this crystal system are listed below, followed by their representations in international notation, Schoenflies notation, orbifold notation, Coxeter notation and mineral examples.Hurlbut, Cornelius S.; Klein, Cornelis, 1985, ''Ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crystallographic
Crystallography is the branch of science devoted to the study of molecular and crystalline structure and properties. The word ''crystallography'' is derived from the Ancient Greek word (; "clear ice, rock-crystal"), and (; "to write"). In July 2012, the United Nations recognised the importance of the science of crystallography by proclaiming 2014 the International Year of Crystallography.UN announcement "International Year of Crystallography" iycr2014.org. 12 July 2012 Crystallography is a broad topic, and many of its subareas, such as , are themselves important scientific topics. Crystallography ranges from the fundamentals o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
