Cornubite Field of view: 1 mm Locality: Daly Mine, Daly Gorge, North Flinders Ranges, South Australia Locality at mindat.org: Daly Mine, Yudnamutana District, Arkaroola (Arkaroola Wilderness Sanctuary; Arkaroola Station), Pastoral Unincorporated Area, South Australia, Australia — Photo: Henk Smeets – tomeikminerals.com · CC BY 4.0
Cornubite
Cornubite is a rare secondary copper arsenate mineral with formula: Cu5(AsO4)2(OH)4. It was first described for its discovery in 1958 in Wheal Carpenter, Gwinear, Cornwall, England, UK. The name is from Cornubia, the medieval Latin name for Cornwall. It is a dimorph of cornwallite, and the arsenic analogue of pseudomalachite.
Intro adapted from Wikipedia (CC BY-SA).
Cornubite is an IMA-recognized mineral species in the arsenate class, with the chemical formula Cu₅(AsO₄)₂(OH)₄.
It crystallizes in the triclinic crystal system (space group P-1).
Key properties: Mohs hardness 4; specific gravity 4.64; Pale green streak; Vitreous luster; refractive index 1.885; optically biaxial.
IMA symbol Cnb, IMA status: approved, named in 1959.
Found as a rare secondary mineral in oxidized copper deposits.
It is found associated with Cornwallite, chalcophyllite, olivenite, liroconite, chenevixite, clinoclase, pseudomalachite, bayldonite, parnauite, tyrolite, azurite, malachite, cuprite.
The name comes from Cornubia, the Latin name for Cornwall, source of the first specimens.