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Formula: PbGa3(AsO4)(SO4)(OH)6
Arsenate, beudantite group,
gallium-bearing mineral
Specific gravity: 4.87 calculated
Hardness: 4
Streak: Pale yellow, white
Colour: Pale yellow, greenish, cream-coloured
Environments
Gallobeudantite was approved in 1994, but to date (June 2022) it has been reported only from the type locality.
Localities
At the type locality, the Tsumeb Mine, Tsumeb, Oshikoto Region, Namibia, gallobeudantite occurs as a rare
secondary mineral in vugs in a single, blackish specimen of massive
copper ore, approximately 5 cm across. The host material consists mainly of aligned
inclusions of renierite, up to 3 mm long, in a granular matrix consisting
largely of a germanite-like mineral. The
renierite contains irregular inclusions of
gallite up to 75 microns across, and one end of the section contains inclusions
of antimony-free gallium-bearing
tennantite. A thin rim of
chalcocite emphasises the granular texture of the
germanite-like phase, and all minerals are cut by irregular, hairline veinlets
of chalcocite. Disseminated on the surface of the specimen are local, minute
patches of hematite and goethite,
sparse crystals of stolzite, and dots of spongy
mercury-bearing silver. One end of the
specimen has a thin, discontinuous veinlet, about 1 mm long, of otjisumeite
(CM34: 1305-1315).
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