Keyite Locality: Tsumeb Mine (Tsumcorp Mine), Tsumeb , Otjikoto (Oshikoto) Region, Namibia ( Locality at mindat.org ) Blue keyite on greenish adamite. Microprobed. Picture width 2 mm. Collection and photograph Christian Rewitzer — Photo: Christian Rewitzer · CC BY-SA 3.0
Keyite
A rare copper-zinc-cadmium arsenate named for American dealer Charles Locke Key, who supplied the first specimens.
Intro adapted from Wikipedia (CC BY-SA).
Keyite is an IMA-recognized mineral species in the arsenate class, with the chemical formula ( ₀.₅Cu₀.₅)CuCdZn₂(AsO₄)₃·H₂O.
It crystallizes in the monoclinic crystal system (space group I2/a). It is a member of the Alluaudite structural group.
Key properties: Mohs hardness 3.5–4; specific gravity 4.2; Pale blue streak; refractive index 1.835; optically biaxial.
IMA symbol Key, IMA status: approved, named in 1975.
Found as a secondary mineral in the oxidized zone of a dolostone-hosted hydrothermal polymetallic ore deposit.
It is found associated with Cuprian adamite, schulténite, metazeunerite, zincian olivenite, tennantite.
The mineral was named to honor Charles Locke Key (1935–), Windhoek, Namibia, American mineral dealer who furnished the first specimen.