conichalcite, calcite : Ojuela Mine, Mapimí, Mapimí Municipality, Durango, Mexico — Photo: Géry PARENT · Public domain
Conichalcite
A grass-green calcium-copper arsenate forming botryoidal crusts in the oxidized zones of metal deposits.
Intro adapted from Wikipedia (CC BY-SA).
Conichalcite is an IMA-recognized mineral species in the arsenate class, with the chemical formula CaCu(AsO₄)(OH).
It crystallizes in the orthorhombic crystal system (space group P2_12_12_1). It is a member of the Adelite structural group.
Key properties: Mohs hardness 4.5; specific gravity 4.33; typically green; Green streak; Vitreous to somewhat greasy luster; refractive index 1.809; optically biaxial.
IMA symbol Con, grandfathered status — known before the IMA’s founding, named in 1849.
Occurs as an uncommon secondary mineral in the oxidized zone of copper deposits, typically an alteration product of enargite.
It is found associated with Austinite, olivenite, clinoclase, libethenite, chenevixite, brochantite, malachite, azurite, jarosite, “limonite”.
Its name comes from the Greek for lime and copper, as both elements are essential to the composition.
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