"Boehmite"@en . "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 n\u03B1 = 1.644 - 1.648, n\u03B2 = 1.654 - 1.657 and n\u03B3 = 1.661 - 1.668. Boehmite occurs in tropical laterites and bauxites developed on alumino-silicate bedrock. It was first described in 1927 and named for German geologist Johann B\u00F6hm (1857\u20131938)."@en . . . "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 n\u03B1 = 1.644 - 1.648, n\u03B2 = 1.654 - 1.657 and n\u03B3 = 1.661 - 1.668. Boehmite occurs in tropical laterites and bauxites developed on alumino-silicate bedrock. It was first described in 1927 and named for German geologist Johann B\u00F6hm (1857\u20131938)."@en .