Galloplumbogummite

galloplumbogummite

germanite

renierite

chalcocite

Images

Formula: Pb(Ga,Al,Ge)3(PO4)2(OH)6
Phosphate, plumbogummite group, gallium- and germanium- bearing mineral
Specific gravity: 4.62 calculated
Streak: White
Colour: Colourless to frosted white
Luminescence: Not fluorescent under UV
Environments

Sedimentary environments
Hydrothermal environments

Galloplumbogummite was approved in 2010, but to date (July 2022) it has been reported only from the type locality.

Localities

At the type locality, the Tsumeb Mine, Tsumeb, Oshikoto Region, Namibia, galloplumbogummite formed by alteration of germanium-gallium minerals in the second oxidised zone of the dolostone-hosted, polymetallic, hydrothermal ore. It was found in millimeter-sized vugs in massive germanite-renierite ore associated with chalcocite, cadmium-rich sphalerite, galena and pyrite. The galloplumbogummite occurs as colourless rhombohedral crystals up to 0.15 mm. The crystals show strong chemical zonation with substitutions of Al,Ga,Ge for each other, also Ca for Pb and S for P (AM 101.6.1492-1493).

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