/puy"reuh klawr', -klohr'/, n.
a mineral, chiefly composed of niobates of the cerium metals, occurring in syenites in the form of brown crystals.
[1820-30; < G Pyrochlor. See PYRO-, CHLOR-1]

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      a complex oxide mineral [(Na, Ca)2Nb2O6(OH,F)] composed of niobium, sodium, and calcium that forms brown to black, glassy octahedral crystals and irregular masses. Tantalum atoms replace niobium atoms in the chemical structure, so that pyrochlore forms a solid-solution series with the mineral microlite [(Na,Ca)2Ta2O6(O,OH,F)]. For detailed physical properties, see oxide mineral (table).

      Pyrochlore is found in alkaline rocks, their associated pegmatites, in metamorphic contact zones, and in greisen (a type of granite composed chiefly of quartz and light green mica). Such rocks have been recognized at Stavern and Lurvik, Nor.; Alnö, Swed.; Brocq en Menet, Fr.; and in Maine, Wisconsin, California, and Colorado, U.S. Microlite occurs in the albitized zones of granite pegmatites, as at Låndas, Nor.; Varuträsk, Swed.; Igaliko, Greenland; and in Connecticut, U.S.

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Universalium. 2010.

Look at other dictionaries:

  • Pyrochlore — Pyr o*chlore, n. [Pyro + Gr. ? pale green.] (Min.) A niobate of calcium, cerium, and other bases, occurring usually in octahedrons of a yellowish or brownish color and resinous luster; so called from its becoming grass green on being subjected to …   The Collaborative International Dictionary of English

  • Pyrochlore — Infobox mineral name = Pyrochlore category = Oxide mineral boxwidth = boxbgcolor = caption = formula = (Na,Ca)2Nb2O6(OH,F) molweight = color = Brown, yellow brown, reddish brown, orange, black habit = disseminated granular subhedral system =… …   Wikipedia

  • pyrochlore — pirochloras statusas T sritis chemija apibrėžtis Mineralas. formulė (Na,Ca)₂(Nb,Ti,Ta)₂O₆(OH,F,O) atitikmenys: angl. pyrochlore rus. пирохлор …   Chemijos terminų aiškinamasis žodynas

  • pyrochlore — ˈpīrəˌklō(ə)r noun ( s) Etymology: German pyrochlor, from pyr + Greek chlōros greenish yellow more at yellow : a brown or dark reddish mineral NaCaCb2O6F that is isomorphous with microlite and is an oxide and fluoride of sodium, calcium, and… …   Useful english dictionary

  • pyrochlore — noun A mineral whose composition is that of a mixed niobate mostly of sodium, calcium and cerium, (Na,Ca)NbO(OH,F) …   Wiktionary

  • pyrochlore — (pi ro klo r ) s. m. Titanate de chaux engagé dans la syénite de Norwége …   Dictionnaire de la Langue Française d'Émile Littré

  • pyrochlore — py·ro·chlore …   English syllables

  • Niobium — zirconium ← niobium → molybdenum V ↑ Nb ↓ Ta …   Wikipedia

  • List of minerals (complete) — It is currently not possible to have a complete list of minerals . The International Mineralogical Association (IMA) is the international group that recognises new minerals and new mineral names. However, minerals discovered before 1959 did not… …   Wikipedia

  • Pyrochlor — Chemische Formel Ca2Nb2O7 [1] Mineralklasse Oxide und Hydroxide 4.DH.15 (8. Auflage: I …   Deutsch Wikipedia

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