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Formula: Pb(Ga,Al,Ge)3(PO4)2(OH)6
Phosphate, plumbogummite group,
alunite supergroup,
gallium- and germanium- bearing
mineral
Crystal System: Trigonal
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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