biotite

biotite
—biotitic /buy'euh tit"ik/, adj.
/buy"euh tuyt'/, n.
a very common mineral of the mica group, occurring in black, dark-brown, or dark-green sheets and flakes: an important constituent of igneous and metamorphic rocks.
[1860-65; named after J. B. Biot (1774-1862), French mineralogist and mathematician; see -ITE1]

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or black mica

Silicate mineral in the common mica group.

It is abundant in metamorphic rocks, in pegmatites, and in granites and other igneous rocks. Biotite is a layer silicate structure in which aluminum and silicon occur in infinitely extending Si-Al-O sheets that alternate with potassium-rich and magnesium-(and iron-) containing sheets.

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also called  black mica,  

      a silicate mineral in the common mica group. It is abundant in metamorphic rocks (both regional and contact), in pegmatites, and also in granites and other intrusive igneous rocks. For chemical formula and detailed physical properties, see mica (table).

      Biotite is regarded as a mixture composed of variable proportions of four basic aluminosilicates of potassium, iron, magnesium, or aluminum: annite, K2Fe6(Si6Al2O20)(OH)4; siderophyllite, K2Fe5Al(Si5Al3O20)(OH)4; phlogopite, K2Mg6(Si6Al2O20)(OH)4; and eastonite, K2Mg5A1(Si5Al3O20)(OH)4. Biotite is arbitrarily designated as having a magnesium-to-iron ratio less than 2:1.

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Universalium. 2010.

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  • Biotite — is a common phyllosilicate mineral within the mica group, with the approximate chemical formula K(Mg, Fe)3AlSi3O10(F, OH)2. More generally, it refers to the dark mica series, primarily a solid solution series between the iron endmember annite,… …   Wikipedia

  • Biotite — Catégorie IX : silicates[1] Biotite Monte Somma Italie (XX 5 mm) …   Wikipédia en Français

  • biotite — [ bjɔtit ] n. f. • 1848; de J. B. Biot, n. pr. ♦ Minéral. Variété de mica noir, utilisée comme matériau d isolation. ● biotite nom féminin (de J. B. Biot, nom propre) Mica monoclinique se présentant en lamelles hexagonales, de couleur noire et… …   Encyclopédie Universelle

  • Biotite — Bi o*tite, n. [From Biot, a French naturalist.] (Min.) Mica containing iron and magnesia, generally of a black or dark green color; a common constituent of crystalline rocks. See {Mica}. [1913 Webster] …   The Collaborative International Dictionary of English

  • biotite — [bī′ə tīt΄] n. [Ger biotit: so named after J. B. Biot (1774 1862), Fr physicist + it, ITE1] a dark colored, soft, monoclinic mica, K(Mg,Fe) 3 (Al,Fe)Si3O10 (OH) 2, found in igneous, metamorphic, and sedimentary rocks …   English World dictionary

  • biotite — Mica Mi ca, n. [L. mica crumb, grain, particle; cf. F. mica.] (Min.) The name of a group of minerals characterized by highly perfect cleavage, so that they readily separate into very thin leaves, more or less elastic. They differ widely in… …   The Collaborative International Dictionary of English

  • biotite — Mica Mi ca, n. [L. mica crumb, grain, particle; cf. F. mica.] (Min.) The name of a group of minerals characterized by highly perfect cleavage, so that they readily separate into very thin leaves, more or less elastic. They differ widely in… …   The Collaborative International Dictionary of English

  • biotite — biotitas statusas T sritis chemija apibrėžtis Mineralas. formulė K(Mg,Fe,Mn)₃[(OH,F)₂|(Al,Fe)Si₃O₁₀] atitikmenys: angl. biotite rus. биотит …   Chemijos terminų aiškinamasis žodynas

  • biotite — noun Etymology: German Biotit, from Jean B. Biot died 1862 French mathematician Date: 1862 a generally black or dark green form of mica that is a constituent of crystalline rocks and consists of a silicate of iron, magnesium, potassium, and… …   New Collegiate Dictionary

  • biotite — noun /ˈbaɪəˌtaɪt/ A dark brown mica; it is a mixed aluminosilicate and fluoride of potassium, magnesium and iron …   Wiktionary

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