twins may be multiple, with serrated re-entrants. It is brittle, with an uneven fracture, hardness and specific gravity 6.13. It is readily soluble in hydrochloric acid HCl and slowly soluble in nitric acid HNO3. It is not radioactive. Environment Tsumebite is a rare secondary mineral in the oxidised zone of some arsenic-bearing lead-copper deposits, with other lead-bearing phosphates and sulfates. Associated minerals include azurite, smithsonite, malachite, cerussite, mimetite, wulfenite and olivenite. The type locality is the Tsumeb mine, Tsumeb, Otjikoto Region, Namibia. The Handbook of Mineralogy states that the type material was destroyed by bombing, but does not indicate when or where. Tsumebite occurs at Morenci, Arizona, predominantly as twinned crystals associated with wulfenite, olivenite and the hyalite variety of opal. At Broken Hill, New South Wales, Australia, tsumebite has been found as lustrous pale blue to bluish green crystals. It usually occurs with yellow crusts of corkite-hinsdalite, colorless to white pyromorphite needles and sprays of pale greyish green zincian libethenite. Less commonly found with scholzite and torbernite. References LaForge (1938) American Mineralogist: 23: 772 External links Jmol: http://rruff.geo.arizona.edu/AMS/viewJmol.php?id=14449 Phosphate minerals Lead minerals Copper(II) minerals Monoclinic minerals Minerals in space group 11