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For Enoch Powell, see here. For his political philosophy known as Powellism, see here.

CategoryMineral Species
Chemical formulaCaMoO4
Molecular Weight200.02 gm
ColorYellow, brown, blue, black
Crystal habitMassive to Crystaline
Crystal systemTetragonal - Dipyramidal
CleavageDistinct on the [111]
Mohs Scale hardness3.5-4
Refractive indexnω = 1.974 nε = 1.984
Optical PropertiesUniaxial (+)
Birefringenceδ = 0.010
Ultraviolet fluorescenceNone
Streaklight yellow
Density4.25 g/cm3

Powellite is a calcium molybdate mineral with formula CaMoO4. Powellite crystallizes with tetragonal - dipyramidal crystal structure as transparent adamantine blue, greenish brown, yellow to grey typically anhedral forms. It exhibits distinct cleavage and has a brittle to conchoidal fracture. It has a Mohs hardness of 3.5 to 4 and a specific gravity is 4.34. It forms a solid solution series with scheelite (calcium tungstate, CaWO4). It has refractive index values of nω=1.974 and nε=1.984.

Powellite was first described in 1891 in the Peacock Mine, Adams County, Idaho and named for American explorer and geologist, John Wesley Powell (1834-1902).


  • Palache, C., H. Berman, and C. Frondel (1951) Dana’s System of Mineralogy, (7th edition), v. II, pp. 1079–1081.
  • Webmineral data
  • Mindat with location data
  • Mineral Data Publishing PDF
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Powellite". A list of authors is available in Wikipedia.
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