Algodonite

Algodonite is a copper arsenide mineral with formula: Cu₆As. It is a gray white metallic mineral crystallizing in the hexagonal system. It has a Mohs hardness of 4 and a specific gravity of 8.38 – 8.72.

Algodonite
Algodonite – Houghton County, Michigan, US
General
Category	Sulfide mineral
Formula	Cu6As
IMA symbol	Ago[1]
Strunz classification	2.AA.10a
Crystal system	Hexagonal
Crystal class	Dihexagonal dipyramidal (6/mmm) H-M symbol: (6/m 2/m 2/m)
Space group	P63/mmc
Unit cell	a = 2.6, c = 4.228 [Å]; Z = 2
Identification
Formula mass	456.2 g/mol
Color	Gray, silver white, steel gray, tarnishes dull bronze
Crystal habit	Massive, granular. Common texture observed in granite and other igneous rock
Fracture	Sub-conchoidal
Mohs scale hardness	4
Luster	Metallic
Diaphaneity	Opaque
Specific gravity	8.38 (measured), 8.72 (calculated)
Other characteristics	Non-magnetic, non-fluorescent
References	[2][3][4]

It was first described in 1857 from the Algodones silver mine, Coquimbo, Chile.