Domeykite

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Domeykite
Domeykite.jpg
General
CategoryArsenide mineral
Formula
(repeating unit)
Cu3As
Strunz classification2.AA.10b
Crystal systemIsometric
Crystal classHextetrahedral (43m)
H-M symbol: (4 3m)
Space groupI43d
Unit cella = 9.62 Å; Z = 16
Identification
Formula mass265.56 g/mol
ColorTin-white to steel-gray
Crystal habitReniform, botryoidal; massive
CleavageNone
TenacityBrittle - sectile
Mohs scale hardness3-3.5
LusterMetallic
StreakBlack gray
DiaphaneityOpaque
Specific gravity7.2 - 8.1, average = 7.65
Other characteristicsTarnishes pale yellow, then pale brown, and finally to iridescence
References[1][2][3]

Domeykite is a copper arsenide mineral, Cu3As. It crystallizes in the isometric system, although crystals are very rare. It typically forms as irregular masses or botryoidal forms. It is an opaque, white to gray (weathers brassy) metallic mineral with a Mohs hardness of 3 to 3.5 and a specific gravity of 7.2 to 8.1[1][3]

It was first described in 1845 in the Algodones mines, Coquimbo, Chile. It was named after Polish mineralogist Ignacy Domeyko (1802–1889) by Wilhelm Haidinger.[2]

Uses[edit]

Domeykite, being a minor copper ore is used for obtaining copper. It can also be polished and used for ornamental purposes.[4]

Crystal structure of domeykite
Mohawkite nugget, a mixture of domeykite, algodonite and native copper (50x40x28 mm)

See also[edit]

References[edit]