Tsumebite from Tsumeb Mine, Tsumeb, Oshikoto Region, Namibia. Collection and photograph Christian Rewitzer. — Photo: Christian Rewitzer · CC BY-SA 3.0
Tsumebite
A rare lead-copper phosphate named in 1912 for Namibia's legendary Tsumeb mine.
Intro adapted from Wikipedia (CC BY-SA).
Tsumebite is an IMA-recognized mineral species in the phosphate class, with the chemical formula Pb₂Cu(PO₄)(SO₄)(OH).
It crystallizes in the monoclinic crystal system (space group P2_1/m). It is a member of the Brackebuschite structural group.
Key properties: Mohs hardness 3.5; specific gravity 6.01–6.13; Vitreous, brilliant luster; refractive index 1.921; optically biaxial.
IMA symbol Tsu, grandfathered status — known before the IMA’s founding, named in 1912.
A rare secondary mineral found in the oxidized zone of some arsenic-bearing Pb–Cu deposits.
It is found associated with Azurite, smithsonite, malachite, cerussite, mimetite, wulfenite, olivenite.
The name refers to its first-noted occurrence at Tsumeb, Namibia.