Tsumebite

phosphate

Tsumeb

Formula: Pb2Cu(PO4)(SO4)(OH)
Compound phosphate, brackebuschite group
Specific gravity: 6.13
Hardness: 3½
Streak: White to faint green
Colour: Emerald-green sometimes bluish green; green in transmitted light
Solubility: Readily soluble in hydrochloric acid and slowly soluble in nitric acid
Environments:

Hydrothermal environments

Tsumebite is a rare secondary mineral in polymetallic ore deposits, occurring in the oxidised zone of some arsenic-bearing lead - copper deposits with other lead-bearing phosphates and sulphates, associated with azurite, smithsonite, malachite, cerussite, mimetite, wulfenite and olivenite.

At Block 14 open cut, Broken Hill, New South Wales, Australia, tsumebite has been found on etched garnet-quartz rocks associated with corkite-hinsdalite, pyromorphite, zinc-rich libethenite, and less commonly with scholzite and torbernite.

At the type locality, the Tsumeb Mine, Oshikoto Region, Namibia, tsumebite is associated with smithsonite, cerussite, malachite and azurite. Chemically verified Tsumeb tsumebite is rare and most unanalysed specimens labeled tsumebite are probably arsentsumebite.

At Morenci, Arizona, USA, tsumebite occurs predominantly as twinned crystals associated with wulfenite, olivenite and opal variety hyalite.

At the Reward mine, Inyo county, California, USA, tsumebite is associated with pyromorphite, corkite and other phosphates.

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