coesite


coesite
/koh"suyt/, n. Mineral.
a rare form of silicon dioxide, a denser polymorph of quartz, originally synthesized from quartz at high temperatures and pressures: later discovered in nature. Cf. stishovite.
[1950-55; named after Loring Coes, Jr., 20th-century American who synthesized it; see -ITE1]

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      a high-pressure polymorph (crystal form) of silica, silicon dioxide (SiO2). It has the same chemical composition as the minerals cristobalite, stishovite, quartz, and tridymite but possesses a different crystal structure. Because of the very high pressure necessary for its formation, it does not occur naturally in the Earth's crust. Artificially produced in 1953 by the American chemist Loring Coes, Jr., it was discovered in nature in 1960 in the sandstone on the floor of Meteor Crater, near Winslow, Ariz. There coesite was formed from quartz under the high temperature and pressure generated by the large meteorite's impact. It has since been found in the craters of other large meteorites. Quartz should change to coesite at depths of 60 to 100 km (40 to 60 miles) below the Earth's surface. In 1984 coesite was found in ultrahigh-pressure metamorphic rocks of the Dora Maira region, Italy. For detailed physical properties, see silica mineral (table).

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Universalium. 2010.

Look at other dictionaries:

  • Coesite — Coésite La coésite est une polymorphe de la silice produite au cours d un métamorphisme de très haute pression (vers 30 kilobars, soit 100 km de profondeur). On en trouve dans le massif de Dora Maira, dans les Alpes italiennes. La coésite a été… …   Wikipédia en Français

  • coésite — ● coésite nom féminin Minéral polymorphe de haute pression du quartz …   Encyclopédie Universelle

  • coesite — ☆ coesite [kō′zīt΄, kō′sīt΄ ] n. [after Loring Coes, Jr. (1915 ), U.S. mineralogist + ITE1] a very hard, monoclinic form of silica, SiO2, produced under very great pressure and found in the sandstone of large meteor craters …   English World dictionary

  • Coesite — Atomic structure of coesite Coesite[p] is a form (polymorph) of silicon dioxide SiO2 that is formed when very high pressure (2–3 gigapascals), and moderately high temperature (700 °C or 1,300 °F), are applied to quartz. Coesite was… …   Wikipedia

  • Coésite — La coésite est une polymorphe de la silice produite au cours d un métamorphisme de très haute pression (vers 30 kilobars, soit 100 km de profondeur). On en trouve dans le massif de Dora Maira, dans les Alpes italiennes. La coésite a été… …   Wikipédia en Français

  • coesite — koesitas statusas T sritis chemija apibrėžtis Aukštoje temperatūroje ir padidintame slėgyje susidariusi kvarco atmaina. formulė SiO₂ atitikmenys: angl. coesite rus. коэсит …   Chemijos terminų aiškinamasis žodynas

  • coesite — noun A high pressure polymorph of silica found in extreme conditions such as the impact craters of meteorites, with the chemical composition of silicon dioxide, SiO …   Wiktionary

  • coesite — coes·ite …   English syllables

  • coesite — ˈkōˌzīt noun ( s) Etymology: Loring Coes, Jr., died 1978 American chemist + English ite : a dense crystalline silica formed from quartz under great heat and pressure and found in meteorite craters …   Useful english dictionary

  • 13778-38-6 — Coésite La coésite est une polymorphe de la silice produite au cours d un métamorphisme de très haute pression (vers 30 kilobars, soit 100 km de profondeur). On en trouve dans le massif de Dora Maira, dans les Alpes italiennes. La coésite a été… …   Wikipédia en Français


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