Specific gravity: 4.4
Colour: Steel grey to iron black
Solubility: Slightly soluble in nitric acid
Common impurities: Sb,Fe,Pb,Zn,Ag,Ge
Enargite is a comparatively rare mineral, found in vein and replacement deposits formed at moderate temperatures
associated with pyrite,
Enargite occurs in arsenic containing copper ore veins.
At the Gregory mine, Ashover, Derbyshire, England, UK, enargite has been found with calcite (RES p103).
enargite and pyrite to Fe-tennantite, chalcopyrite and sulphur
4Cu3AsS4 + 4FeS2 → Cu10Fe2As4S13 + 2CuFeS2 + 7/2S2
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