Domeykite

Domeykite
General
Category	Arsenide mineral
Chemical formula	Cu3As
Strunz classification	02.AA.10b
Crystal symmetry	Isometric hextetrahedral H-M symbol: (43m) Space group: I43d
Unit cell	a = 9.62 Å; Z = 16
Identification
Molar mass	265.56
Color	Tin-white to steel-gray
Crystal habit	Reniform, botryoidal; massive
Crystal system	Isometric
Cleavage	None
Tenacity	Brittle - sectile
Mohs scale hardness	3-3.5
Luster	Metallic
Streak	Black gray
Diaphaneity	Opaque
Specific gravity	7.2 - 8.1, average = 7.65
Other characteristics	Tarnishes pale yellow, then pale brown, and finally to iridescence
References

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.

It was first described in 1845 in the Algodones mines, Coquimbo, Chile. It was named for Lithuanian mineralogist Ignacy Domeyko (1802-89).

Crystal structure of domeykite

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

See also

• List of minerals
• List of minerals named after people

References

• Mineral galleries