Domeykite

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.^[2][4]

Domeykite
General
Category	Arsenide mineral
Formula	Cu3As
IMA symbol	Do[1]
Strunz classification	2.AA.10b
Crystal system	Isometric
Crystal class	Hextetrahedral (43m) H-M symbol: (4 3m)
Space group	I43d
Unit cell	a = 9.62 Å; Z = 16
Identification
Formula mass	265.56 g/mol
Color	Tin-white to steel-gray
Crystal habit	Reniform, botryoidal; massive
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	[2][3][4]

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.^[3]

Uses

Domeykite, being a minor copper ore, is used for obtaining copper. It can also be polished and used for ornamental purposes.^[5]

Crystal structure of domeykite

Mohawkite nugget, a mixture of domeykite, algodonite and native copper (50 × 40 × 28 mm)

See also

• List of minerals
• List of minerals named after people