Anhydrous arsenate containing hydroxyl, dimorph of cornwallite
Specific gravity: 4.64
Streak: Pale green
Colour: Apple green to dark green
Cornubite is a rare secondary mineral in oxidised copper deposits. Near Reichenbach
in the Oderwald, Germany, cornubite occurs in a silicified quartz vein.
At the type locality, Wheal Carpenter, Cornwall, England cornubite occurs in copper-tin-silver bearing hydrothermal veins, associated with cornwallite, chalcophyllite, olivenite, liroconite, chenevixite, clinoclase, pseudomalachite, bayldonite, parnauite, tyrolite, azurite, malachite, cuprite, chrysocolla and quartz.
At the San Rafael mine, Nye county, Nevada, USA, cornubite has been found with olivenite and strashimirite.
At Bou Azzer, Morocco cornubite has been found in quartz cavities together with scorodite.