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Formula: Al(UO2)2(PO4)2(OH).8H2O
Hydrated phosphate containing hydroxyl, uranyl mineral
Crystal System: Monoclinic
Specific gravity: 3.4 measured, 3.33 calculated
Hardness: 2 to 3
Streak: Yellow-white
Colour: Yellow-green
Luminescence: Fluorescent, green under long wave UV and pale green under short wave
Environments
Pegmatites
Hydrothermal environments
Threadgoldite occurs as a rare secondary mineral in the
uraniferous zone of a complex zoned granite
pegmatite. Associated minerals include
meta-autunite,
phosphuranylite, phuralumite,
bolivarite, upalite,
eylettersite and mundite
(HOM).
Localities
At the type locality, the Kobokobo pegmatite, Shabunda Territory, South Kivu, DR Congo, threadgoldite occurs
with phuralumite and upalite as
greenish-yellow micaceous tabular crystals up to 1 mm long
(AM 65.209).
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