Abstract

Hashemite, Ba(Cr,S)O 4 , from west-central Jordan is associated with chromian ettringite, apatite, and calcite in a phosphatic carbonate rock analogous to the Hatrurim Formation in Israel. The mineral is orthorhombic, Pnma, with a = 9.112(2)Aa, b = 5.541(1)Aa, c = 7.343(1)Aa, Z = 4. It occurs as small, euhedral, dark-brown, commonly zoned crystals with an averaged D(meas.) = 4.59 g/cm 3 and a hardness of 3.5. Hashemite is biaxial (+): refractive indices on light and dark material are: (dark) alpha = 1.952(2), beta = 1.960(2), gamma = 1.977(2); (light) alpha = 1.810(2), beta = 1.813(2), gamma = 1.824(2). 2V 2 (+) varies from 35 degrees to 57 degrees . Microprobe analyses of zoned crystals yield BaO = 61.4, CrO 3 = 31.3, and SO 3 = 7.50 summing to 100.00.--Modified journal abstract.

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