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
Böhmite and Natrolite from Sagåsen (Strandåsen), Mørje, Porsgrunn, Telemark, Norway (Field of view 10 mm)
It was first described by J. de Lapparent in 1927 for an occurrence in the bauxites of Mas Rouge, Les Baux-de-Provence, France, and named[6] for the Bohemian-German chemist Johann Böhm (1895–1952) who carried out X-ray studies of aluminium oxide hydroxides in 1925[7] (and not for the German geologist Johannes Böhm (1857–1938) as often stated).[2][3]
^"The Mineral Boehmite". minerals.net. Retrieved June 10, 2014.
^Sahama, Th. G.; Lehtinen, Martti; Rehtijärvi, Pentti (1973). "Natural boehmite single crystals from Ceylon". Contributions to Mineralogy and Petrology. 39 (2): 171. Bibcode:1973CoMP...39..171S. doi:10.1007/BF00375738. S2CID 129237343.
^Böhm, J. (1925). "Über Aluminium- und Eisenhydroxyde. I". Zeitschrift für anorganische und allgemeine Chemie. 149: 203–216. doi:10.1002/zaac.19251490114.
October 24, 2023
boehmite, böhmite, aluminium, oxide, hydroxide, mineral, component, aluminium, bauxite, dimorphous, with, diaspore, crystallizes, orthorhombic, dipyramidal, system, typically, massive, habit, white, with, tints, yellow, green, brown, impurities, vitreous, pear. Boehmite or bohmite is an aluminium oxide hydroxide g 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 na 1 644 1 648 nb 1 654 1 657 and ng 1 661 1 668 BoehmiteBohmite and Natrolite from Sagasen Strandasen Morje Porsgrunn Telemark Norway Field of view 10 mm GeneralCategoryOxide mineralFormula repeating unit g AlO OH IMA symbolBhm 1 Strunz classification4 FE 15Dana classification6 1 2 1Crystal systemOrthorhombicCrystal classDipyramidal mmm H M symbol 2 m 2 m 2 m Space groupAmamUnit cella 3 693 A b 12 221 A c 2 865 A Z 4IdentificationColorWhite pale greyish brown yellowish or reddish when impure colorless in thin sectionCrystal habitTabular crystal rare fine grained in pisolitic aggregates or disseminatedCleavageVery good on 010 good on 100 and poor on 001 FractureUnevenTenacityBrittleMohs scale hardness3 5LusterVitreous pearly on 010 StreakWhiteDiaphaneityTranslucentSpecific gravity3 02 3 05Optical propertiesBiaxial Refractive indexna 1 644 1 648 nb 1 654 1 657 ng 1 661 1 668Birefringenced 0 017 0 0202V angleMeasured 74 to 88 Calculated 80 DispersionweakReferences 2 3 4 5 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 occurs with kaolinite gibbsite and diaspore in bauxite deposits and with nepheline gibbsite diaspore natrolite and analcime in nepheline pegmatites 4 Industrially it is used as an inexpensive flame retardant additive for fire safe polymers It was first described by J de Lapparent in 1927 for an occurrence in the bauxites of Mas Rouge Les Baux de Provence France and named 6 for the Bohemian German chemist Johann Bohm 1895 1952 who carried out X ray studies of aluminium oxide hydroxides in 1925 7 and not for the German geologist Johannes Bohm 1857 1938 as often stated 2 3 See also EditPseudoboehmite List of minerals List of minerals named after peopleReferences Edit Warr L N 2021 IMA CNMNC approved mineral symbols Mineralogical Magazine 85 3 291 320 Bibcode 2021MinM 85 291W doi 10 1180 mgm 2021 43 S2CID 235729616 a b Boehmite Webmineral data Retrieved 2010 07 10 a b Boehmite Mindat with location data Retrieved 2010 07 10 a b Mineral Data Pub Handbook of Mineralogy The Mineral Boehmite minerals net Retrieved June 10 2014 Sahama Th G Lehtinen Martti Rehtijarvi Pentti 1973 Natural boehmite single crystals from Ceylon Contributions to Mineralogy and Petrology 39 2 171 Bibcode 1973CoMP 39 171S doi 10 1007 BF00375738 S2CID 129237343 Bohm J 1925 Uber Aluminium und Eisenhydroxyde I Zeitschrift fur anorganische und allgemeine Chemie 149 203 216 doi 10 1002 zaac 19251490114 Steven Dutch 2002 Lepidocrocite and Boehmite Structure University of Wisconsin Green Bay Retrieved from https en wikipedia org w index php title Boehmite amp oldid 1177899079, wikipedia, wiki, book, books, library,
