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Tilleyite
Tilleyite is a rarely occurring calcium sorosilicate mineral with formula (sometimes represented as ). It is chemically a calcium silicate with additional carbonate ions. Tilleyite crystallizes in the monoclinic crystal system and forms only poorly developed, irregularly defined, tabular crystals and spherical grains. In its pure form it is colorless and transparent, however due to multiple refractions of light from lattice defects or polycrystalline formation, it can also appear white, with the transparency decreasing accordingly. History Tilleyite was first described from an occurrence at the Crestmore Quarry in Riverside County, California in 1932 by Esper Larsen and Kingsley Dunham, and named after Cecil Edgar Tilley (1894–1973), a professor of geology at the University of Cambridge, in recognition of his contributions to the study of metamorphism. Its type material is held at Harvard University, and the National Museum of Natural History. Crystal Structure Tilley ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Minerals
This is a list of minerals which have Wikipedia articles. Minerals are distinguished by various chemical and physical properties. Differences in chemical composition and crystal structure distinguish the various ''species''. Within a mineral species there may be variation in physical properties or minor amounts of impurities that are recognized by mineralogists or wider society as a mineral ''variety''. Mineral variety names are listed after the valid minerals for each letter. For a more complete listing of all mineral names, see List of minerals recognized by the International Mineralogical Association. A :Varieties that are not valid species: *Adamantine spar (variety of corundum) *Agate (variety of chalcedony and quartz) *Alabaster (variety of gypsum) *Alexandrite (variety of chrysoberyl) *Allingite (synonym of amber) *Alum *Amazonite (variety of microcline) *Amethyst (purple variety of quartz) *Ametrine (variety of quartz) *Ammolite (organic; also a gemstone) *Amos ... [...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] |
Volcanic Rock
Volcanic rocks (often shortened to volcanics in scientific contexts) are rocks formed from lava erupted from a volcano. Like all rock types, the concept of volcanic rock is artificial, and in nature volcanic rocks grade into hypabyssal and metamorphic rocks and constitute an important element of some sediments and sedimentary rocks. For these reasons, in geology, volcanics and shallow hypabyssal rocks are not always treated as distinct. In the context of Precambrian shield geology, the term "volcanic" is often applied to what are strictly metavolcanic rocks. Volcanic rocks and sediment that form from magma erupted into the air are called "pyroclastics," and these are also technically sedimentary rocks. Volcanic rocks are among the most common rock types on Earth's surface, particularly in the oceans. On land, they are very common at plate boundaries and in flood basalt provinces. It has been estimated that volcanic rocks cover about 8% of the Earth's current land surface. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Muck, Scotland
Muck (; ) is the smallest of four main islands in the Small Isles, part of the Inner Hebrides of Scotland. Today, much of the island is used for grazing. Residents use wool to make rugs and clothing. There are several ancient monuments and some facilities for visitors. The few residents are served by a single school, Muck Primary School & Nursery. The island is owned by the MacEwen family. Geology The larger part of the island is formed from olivine-phyric basalt flows erupted during the Palaeocene. Flows of hawaiite can also be found around the south coast. Together these form the Eigg Lava Formation, a greater part of which is exposed on Eigg itself. The lava flows are cut through by a swarm of Palaeocene age basalt and dolerite dykes generally aligned NNW-SSE. A handful of faults are mapped on a similar alignment, the most significant one of which stretches SE from Bagh a Ghallanaichy of Laig. Gabbro is exposed along the eastern side of the bay of Camas Mor whilst on its west ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carlingford, Ireland
Carlingford (; ) is a coastal town and civil parish in northern County Louth, Ireland. For the purposes of local government, the town is part of the Dundalk Municipal District. It is situated on the southern shore of Carlingford Lough with Slieve Foy mountain as a backdrop, sometimes known as Carlingford Mountain. It is the main town on the Cooley Peninsula. Located on the R176/ R173 roads between Greenore and Omeath village, Carlingford is approximately north east (by road) from Dundalk (15.6 km; 9¾ miles directly), north of Dublin and south of the border with Northern Ireland. Carlingford won the Irish Tidy Towns Competition in 1988. Carlingford still retains its medieval layout noticeable by the narrow lanes and small streets. Tholsel Street is where the last of the medieval walled town's gates can still be seen, called "The Tholsel" which apparently was also used as a gaol, on Tholsel Street itself there is still a 16th-century Town House known as the Carlingford ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Limestone
Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science), crystal forms of calcium carbonate . Limestone forms when these minerals Precipitation (chemistry), precipitate out of water containing dissolved calcium. This can take place through both biological and nonbiological processes, though biological processes, such as the accumulation of corals and shells in the sea, have likely been more important for the last 540 million years. Limestone often contains fossils which provide scientists with information on ancient environments and on the evolution of life. About 20% to 25% of sedimentary rock is carbonate rock, and most of this is limestone. The remaining carbonate rock is mostly Dolomite (rock), dolomite, a closely related rock, which contains a high percentage of the mineral Dolomite (mine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gabbro
Gabbro ( ) is a phaneritic (coarse-grained and magnesium- and iron-rich), mafic intrusive igneous rock formed from the slow cooling magma into a holocrystalline mass deep beneath the Earth's surface. Slow-cooling, coarse-grained gabbro is chemically equivalent to rapid-cooling, fine-grained basalt. Much of the Earth's oceanic crust is made of gabbro, formed at mid-ocean ridges. Gabbro is also found as plutons associated with continental volcanism. Due to its variant nature, the term ''gabbro'' may be applied loosely to a wide range of intrusive rocks, many of which are merely "gabbroic". By rough analogy, gabbro is to basalt as granite is to rhyolite. Etymology The term "gabbro" was used in the 1760s to name a set of rock types that were found in the ophiolites of the Apennine Mountains in Italy. It was named after Gabbro, a hamlet near Rosignano Marittimo in Tuscany. Then, in 1809, the German geologist Christian Leopold von Buch used the term more restrictively in his d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wollastonite
Wollastonite is a calcium Silicate minerals, inosilicate mineral (calcium, Casilicon, Sioxygen, O3) that may contain small amounts of iron, magnesium, and manganese substituting for calcium. It is usually white. It forms when impure limestone or Dolomite (rock), 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). Despite its chemical similarity to the compositional spectrum of the pyroxene group of minerals—where magnesium (Mg) and iron (Fe) substitution for calcium ends with diopside and hedenbergite respectively—it is structurally very different, with a third tetrahedron in the linked chain (as opposed to two in the pyroxenes). Production trend ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vesuvianite
Vesuvianite, also known as idocrase, is a green, brown, yellow, or blue silicate mineral. Vesuvianite occurs as tetragonal crystals in skarn deposits and limestones that have been subjected to contact metamorphism. It was first discovered within included blocks or adjacent to lavas on Mount Vesuvius, hence its name. Attractive-looking crystals are sometimes cut as gemstones. Localities which have yielded fine crystallized specimens include Mount Vesuvius and the Ala Valley near Turin, Piedmont. The specific gravity is 3.4 and the Mohs hardness is . The name "vesuvianite" was given by Abraham Gottlob Werner in 1795, because fine crystals of the mineral are found at Vesuvius; these are brown in color and occur in the ejected limestone blocks of Monte Somma. Several other names were applied to this species, one of which, "idocrase" by René Just Haüy in 1796, is now in common use. A sky bluish variety known as cyprine has been reported from Franklin, New Jersey and other loca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grossular
Grossular is a calcium-aluminium species of the garnet group of minerals. It has the chemical formula of Ca3Al2(SiO4)3 but the calcium may, in part, be replaced by ferrous iron and the aluminium by ferric iron. The name grossular is derived from the botanical name for the gooseberry, ''grossularia'', in reference to the green garnet of this composition that is found in Siberia. Other shades include cinnamon brown (cinnamon stone variety), red, and yellow. Grossular is a gemstone. In geological literature, grossular has often been called ''grossularite''. Since 1971, however, use of the term grossularite for the mineral has been discouraged by the International Mineralogical Association. Hessonite Hessonite or "cinnamon stone" is a common variety of grossular with the general formula: Ca3Al2Si3O12. The name comes from the (hēssōn), meaning ''inferior''; an allusion to its lower hardness and lower density than most other garnet species varieties. It has a characteristic red ... [...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] |
Fluorite
Fluorite (also called fluorspar) is the mineral form of calcium fluoride, CaF2. It belongs to the halide minerals. It crystallizes in isometric cubic habit, although octahedral and more complex isometric forms are not uncommon. The Mohs scale of mineral hardness, based on scratch hardness comparison, defines value 4 as fluorite. Pure fluorite is colourless and transparent, both in visible and ultraviolet light, but impurities usually make it a colorful mineral and the stone has ornamental and lapidary uses. Industrially, fluorite is used as a flux for smelting, and in the production of certain glasses and enamels. The purest grades of fluorite are a source of fluoride for hydrofluoric acid manufacture, which is the intermediate source of most fluorine-containing fine chemicals. Optically clear transparent fluorite has anomalous partial dispersion, that is, its refractive index varies with the wavelength of light in a manner that differs from that of commonly used glasses, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
