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torbernite A secondary mineral, with the formula Cu(UO2)2 (PO4)2.8–12H2O; sp. gr. 3.2; hardness 2.5; tetragonal; normally bright emerald-green, but occasionally dark green; pale green streak; vitreous lustre; crystals tabular, square, foliated, scaly aggregates; cleavage perfect basal hardness; occurs in the oxidized zones of veins containing uranium and copper minerals, often with autunite.