Chemistry:Hashemite (mineral)

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Hashemite
Hashemite.jpg
Hashemite from the Lisdan-Siwaga Fault, Hashem Region, Amman, Jordan
General
CategoryChromate minerals
Formula
(repeating unit)
Barium Chromate Ba(S,Cr)O4
Crystal systemOrthorhombic
Identification
ColorBrown to yellow
CleavagePerfect {001}, good {010} {100}
Mohs scale hardness3.5
|re|er}}Adamantine
DiaphaneityTranslucent
Specific gravity4.54 - 4.59
References[1]

Hashemite is a very rare barium chromate mineral[1] with the formula Ba(Cr,S)O4.[2] It is a representative of natural chromates - a relatively small and rare group of minerals. Hashemite is the barium-analogue of tarapacáite. It is also the chromium-analogue of baryte, and belongs to the baryte group of minerals. Hashemite is stoichiometrically similar to crocoite and chromatite.[1] Hashemite is orthorhombic, with space group Pnma. I was found together with chromium-bearing ettringite and an apatite group mineral in the Hatrurim Formation,[2] known for the occurrence of rocks formed due to natural pyrometamorphism.[1] Hashemite is named after the Hashemite Kingdom of Jordan.[2]

References

  1. 1.0 1.1 1.2 1.3 "Hashemite: Hashemite mineral information and data". http://www.mindat.org/min-1823.html. Retrieved 5 March 2016. 
  2. 2.0 2.1 2.2 Hauff, P.L., Foord, E.E., and Rosenblum, S., 1983. Hashemite, Ba(Cr,S)O4, a new mineral from Jordan. American Mineralogist 68, 1223-1225.