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Sillimanite
Sillimanite or fibrolite is an aluminosilicate mineral with the chemical formula Al2SiO5. Sillimanite is named after the American chemist Benjamin Silliman (1779–1864). It was first described in 1824 for an occurrence in Chester, Connecticut. Occurrence Sillimanite or fibrolite is one of three aluminosilicate polymorphs, the other two being andalusite and kyanite. A common variety of sillimanite is known as ''fibrolite'', so named because the mineral appears like a bunch of fibres twisted together when viewed in thin section or even by the naked eye. Both the fibrous and traditional forms of sillimanite are common in metamorphosed sedimentary rocks. It is an index mineral indicating high temperature but variable pressure. Example rocks include gneiss and granulite. It occurs with andalusite, kyanite, potassium feldspar, almandine, cordierite, biotite and quartz in schist, gneiss, hornfels and also rarely in pegmatites. Dumortierite and mullite are similar mineral species found ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nesosilicate
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 seaw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Granulite
Granulites are a class of high-grade metamorphic rocks of the granulite facies that have experienced high-temperature and moderate-pressure metamorphism. They are medium to coarse–grained and mainly composed of feldspars sometimes associated with quartz and anhydrous ferromagnesian minerals, with granoblastic texture and gneissose to massive structure.D.R. Bowes (1989), ''The Encyclopedia of Igneous and Metamorphic Petrology''; Van Nostrand Reinhold They are of particular interest to geologists because many granulites represent samples of the deep continental crust. Some granulites experienced decompression from deep in the Earth to shallower crustal levels at high temperature; others cooled while remaining at depth in the Earth. The minerals present in a granulite will vary depending on the parent rock of the granulite and the temperature and pressure conditions experienced during metamorphism. A common type of granulite found in high-grade metamorphic rocks of the conti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
New Castle County, Delaware
New Castle County is the northernmost of the three List of counties in Delaware, counties of the U.S. state of Delaware (New Castle, Kent County, Delaware, Kent, and Sussex County, Delaware, Sussex). As of the 2020 United States census, 2020 census, the population was 570,719, making it the most populous county in Delaware, with nearly 60% of the state's population of 989,948. The county seat is Wilmington, Delaware, Wilmington, which is also the state's most populous city. New Castle County is included in the Philadelphia-Camden, New Jersey, Camden-Wilmington, Delaware, Wilmington, Delaware Valley, PA-NJ-DE-MD Metropolitan Statistical Area. The county is named after William Cavendish, 1st Duke of Newcastle (–1676). New Castle County has the highest population and population density of any Delaware county, and it is the smallest county in the state by area. It has more people than the other two counties, Kent County, Delaware, Kent and Sussex County, Delaware, Sussex, combined. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brandywine Springs
Brandywine Springs is a historic area near Newport, Delaware, along the Red Clay Creek. It is noted from early American history as a Revolutionary War encampment of General George Washington's army. In 1826, a large four-storey resort hotel was built in Brandywine Springs. "The resort became an attraction for many persons of distinction and elegance both in national life and in society," wrote one early 20th-century history of the Newark area. Visitors included John Quincy Adams, Henry Clay, and Daniel Webster. The hotel and its grounds were purchased in 1832 by Matthew Newkirk, a wealthy Philadelphia merchant who owned a vacation cottage nearby. Newkirk spent considerable sums to improve the hotel and grounds. But by 1850 the hotel was failing. It was soon leased to Captain Alden Partridge, who opened the National Scientific and Military Academy there. But the school building was destroyed by fire shortly after opening and the school closed. In the 1880s, it became known once ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Porcelain
Porcelain (), also called china, is a ceramic material made by heating Industrial mineral, raw materials, generally including kaolinite, in a kiln to temperatures between . The greater strength and translucence of porcelain, relative to other types of pottery, arise mainly from Vitrification#Ceramics, vitrification and the formation of the mineral mullite within the body at these high temperatures. End applications include tableware, ceramic art, decorative ware such as figurines, and products in technology and industry such as Insulator (electricity), electrical insulators and laboratory ware. The manufacturing process used for porcelain is similar to that used for earthenware and stoneware, the two other main types of pottery, although it can be more challenging to produce. It has usually been regarded as the most prestigious type of pottery due to its delicacy, strength, and high degree of whiteness. It is frequently both glazed and decorated. Though definitions vary, po ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mullite
Mullite or porcelainite is a rare silicate mineral formed during contact metamorphism of clay minerals. It can form two stoichiometric forms: 3 Al2 O32 SiO2 or 2Al2O3 SiO2. Unusually, mullite has no charge-balancing cations present. As a result, there are three different aluminium sites: two distorted tetrahedral and one octahedral. Mullite was first described in 1924 for an occurrence on the Isle of Mull, Scotland. It occurs as argillaceous inclusions in volcanic rocks in the Isle of Mull, inclusions in sillimanite within a tonalite at Val Sissone, Italy and with emerylike rocks in Argyllshire, Scotland. Porcellanite Mullite (porcelainite) can be found as a constituent mineral in a type of thermally-metamorphosed rock called porcellanite. Use in porcelain Mullite is present in the form of needles in porcelain. It is produced during various melting and firing processes, and is used as a refractory material,H. Schneider & S. Komarneni (2005) Mullite. Wiley, VCH, 5 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dumortierite
Dumortierite is a fibrous variably colored aluminium boro-silicate mineral, Al7BO3(SiO4)3O3. It crystallizes in the orthorhombic system typically forming fibrous aggregates of slender prismatic crystals. The crystals are vitreous and vary in color from brown, blue, and green to more rare violet and pink. Substitution of iron and other tri-valent elements for aluminium results in the color variations. It has a Mohs hardness of 7 and a specific gravity of 3.3 to 3.4. Crystals show pleochroism from red to blue to violet. Dumortierite quartz is blue colored quartz containing abundant dumortierite inclusions. Dumortierite was first described in 1881 for an occurrence in Chaponost, in the Rhône-Alps of France and named for the French paleontologist Eugène Dumortier (1803–1873). It typically occurs in high temperature aluminium rich regional metamorphic rocks, those resulting from contact metamorphism and also in boron rich pegmatites. The most extensive investigation on dumort ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pegmatite
A pegmatite is an igneous rock showing a very coarse texture, with large interlocking crystals usually greater in size than and sometimes greater than . Most pegmatites are composed of quartz, feldspar, and mica, having a similar silicic composition to granite. However, rarer intermediate composition and mafic pegmatites are known. Many of the world's largest crystals are found within pegmatites. These include crystals of microcline, quartz, mica, spodumene, beryl, and tourmaline. Some individual crystals are over long. Most pegmatites are thought to form from the last fluid fraction of a large crystallizing magma body. This residual fluid is highly enriched in volatiles and trace elements, and its very low viscosity allows components to migrate rapidly to join an existing crystal rather than coming together to form new crystals. This allows a few very large crystals to form. While most pegmatites have a simple composition of minerals common in ordinary igneous rock ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hornfels
Hornfels is the group name for a set of Metamorphism#Contact .28thermal.29, contact metamorphic rocks that have been baked and hardened by the heat of Intrusive rock, intrusive igneous masses and have been rendered massive, hard, splintery, and in some cases exceedingly tough and durable. These properties are caused by fine grained non-aligned crystals with platy or prismatic Crystal habit, habits, characteristic of metamorphism at high temperature but without accompanying deformation. The term is derived from the German word ''Hornfels'', meaning "hornstone", because of its exceptional toughness and texture both reminiscent of animal horns. These rocks were referred to by miners in northern England as Sharpening stone, whetstones. Most hornfels are fine-grained, and while the original rocks (such as sandstone, shale, slate and limestone) may have been more or less fissile owing to the presence of bedding or Cleavage (geology), cleavage planes, this structure is effaced or rendered ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Schist
Schist ( ) is a medium-grained metamorphic rock generally derived from fine-grained sedimentary rock, like shale. It shows pronounced ''schistosity'' (named for the rock). This means that the rock is composed of mineral grains easily seen with a low-power hand lens, oriented in such a way that the rock is easily split into thin flakes or plates. This texture (geology), texture reflects a high content of platy minerals, such as mica, talc, chlorite group, chlorite, or graphite. These are often interleaved with more granular minerals, such as feldspar or quartz. Schist typically forms during regional metamorphism accompanying the process of mountain building (orogeny) and usually reflects a medium Metamorphism#Metamorphic grades, grade of metamorphism. Schist can form from many different kinds of rocks, including sedimentary rocks such as mudstones and igneous rocks such as tuffs. Schist metamorphosed from mudstone is particularly common and is often very rich in mica (a ''mica schis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quartz
Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The Atom, atoms are linked in a continuous framework of SiO4 silicon–oxygen Tetrahedral molecular geometry, tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical formula of Silicon dioxide, SiO2. Quartz is, therefore, classified structurally as a Silicate mineral#Tectosilicates, framework silicate mineral and compositionally as an oxide mineral. Quartz is the second most abundant mineral in Earth's continental crust, behind feldspar. Quartz exists in two forms, the normal α-quartz and the high-temperature β-quartz, both of which are chiral. The transformation from α-quartz to β-quartz takes place abruptly at . Since the transformation is accompanied by a significant change in volume, it can easily induce microfracturing of ceramics or rocks passing through this temperature threshold. There are many different varieties of quartz, several of which are classifi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biotite
Biotite is a common group of phyllosilicate minerals within the mica group, with the approximate chemical formula . It is primarily a solid-solution series between the iron- endmember annite, and the magnesium-endmember phlogopite; more aluminous end-members include siderophyllite and eastonite. Biotite was regarded as a mineral ''species'' by the International Mineralogical Association until 1998, when its status was changed to a mineral ''group''. The term ''biotite'' is still used to describe unanalysed dark micas in the field. Biotite was named by J.F.L. Hausmann in 1847 in honor of the French physicist Jean-Baptiste Biot, who performed early research into the many optical properties of mica. Members of the biotite group are sheet silicates. Iron, magnesium, aluminium, silicon, oxygen, and hydrogen form sheets that are weakly bound together by potassium ions. The term "iron mica" is sometimes used for iron-rich biotite, but the term also refers to a flaky micace ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
