Boehmite

Boehmite or Böhmite is an aluminium oxide hydroxide (γ-AlO(OH)) mineral, a component of the aluminium ore bauxite. It is dimorphous with diaspore. It crystallizes in the orthorhombic dipyramidal system and is typically massive in habit. It is white with tints of yellow, green, brown or red due to impurities. It has a vitreous to pearly luster, a Mohs hardness of 3 to 3.5 and a specific gravity of 3.00 to 3.07. It is colorless in thin section, optically biaxial positive with refractive indices of nα = 1.644 - 1.648, nβ = 1.654 - 1.657 and nγ = 1.661 - 1.668.

Boehmite occurs in tropical laterites and bauxites developed on alumino-silicate bedrock. It also occurs as a hydrothermal alteration product of corundum and nepheline.

It was first described in 1927 and named for German geologist Johann Böhm (1857–1938).

References

* [http://rruff.geo.arizona.edu/doclib/hom/bohmite.pdf Mineral Data Pub. The University of Arizona]
* [http://webmineral.com/data/Boehmite.shtml Webmineral data]
* [http://www.mindat.org/min-707.html Mindat with location data]
* [http://www.uwgb.edu/DutchS/PETROLGY/LepidocrStruc.HTM Steven Dutch, 2002, Lepidocrocite and Boehmite Structure, University of Wisconsin - Green Bay]


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Look at other dictionaries:

  • Boéhmite — Catégorie IV : oxydes et hydroxydes[1] Boéhmite et Natrolite (blanc) …   Wikipédia en Français

  • Boehmite — Pour les articles homonymes, voir Diaspore. Boehmite Catégorie III : oxydes et hydroxydes Formule brute AlO(OH) …   Wikipédia en Français

  • boehmite — [bām′īt΄, bōm′īt΄] n. [Ger böhmit, after J. Böhm, 20th c. mineralogist] a soft, orthorhombic mineral, hydrous aluminum oxide, AlO(OH), that is a chief component of some bauxites …   English World dictionary

  • boehmite — /bay muyt, boh /, n. a mineral, hydrous aluminum oxide, AlO(OH), a major component of bauxite. [1925 30; < G Böhmit, named after J. Böhm, 20th century German scientist; see ITE1] * * * ▪ mineral       white and relatively soft basic aluminum… …   Universalium

  • boehmite — bemitas statusas T sritis chemija apibrėžtis Mineralas. formulė AlO(OH) atitikmenys: angl. boehmite rus. бемит …   Chemijos terminų aiškinamasis žodynas

  • boehmite — noun Etymology: German Böhmit, from Johann Böhm (Boehm) died 1952 German chemist Date: circa 1929 a mineral consisting of an orthorhombic form of aluminum oxide and hydroxide AlO(OH) found in bauxite …   New Collegiate Dictionary

  • boehmite — noun A mixed oxide and hydroxide of aluminium …   Wiktionary

  • boehmite — boehm•ite [[t]ˈbeɪ maɪt, ˈboʊ [/t]] n. mir a mineral, hydrous aluminum oxide, AlO(OH), a major component of bauxite • Etymology: 1925–30; < G Böhmit, after J. Böhm, 20th cent. German scientist; see ite I …   From formal English to slang

  • boehmite — noun also böhmite ˈbāˌmīt, ˈbōˌm ( s) Usage: sometimes capitalized Etymology: German böhmit, from J.Böhm (Boehm), 20th century German scientist + German it ite …   Useful english dictionary

  • 14457-84-2 — Boehmite Pour les articles homonymes, voir Diaspore. Boehmite Catégorie III : oxydes et hydroxydes Formule brute AlO(OH) …   Wikipédia en Français


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