Tsumebite is a rare phosphate mineral named in 1912 after the locality where it was first found, the Tsumeb mine in Namibia, well known to mineral collectors for the wide range of minerals found there. Tsumebite is a compound phosphate and sulfate of lead and copper, with hydroxyl, formula Pb₂Cu(PO₄)(SO₄)(OH). There is a similar mineral called arsentsumebite, where the phosphate group PO₄ is replaced by the arsenate group AsO₄, giving the formula Pb₂Cu(AsO₄)(SO₄)(OH). Both minerals are members of the brackebuschite group.