Metauranocircite

metauranocircite

autunite

metatorbernite

uranophane

Images

Formula: Ba(U6+O2)2(PO4)2.6H2O
Hydrated phosphate, uranyl mineral, meta-autunite group. Rapid dehydration of uranocircite in dry atmospheres at normal temperature results in metauranocircite (Mindat).
Specific gravity: 3.94
Hardness: 2 to 2½
Streak: Yellowish white
Colour: Greenish yellow, yellowish green
RADIOACTIVE
Environments

Pegmatites
Hydrothermal environments

Metauranocircite occurs typically as a secondary mineral derived from phosphatic uraninite deposits in the oxidised zone of some uranium deposits; it may be primary in low-temperature veins, and it also occurs in granite pegmatites. Associated minerals include autunite, coffinite, haiweeite, meta-autunite, metatorbernite, metatyuyamunite, metauranopilite, phurcalite, torbernite, uraninite, uranophane, uranophane-β and zippeite group minerals (HOM, Webmin, Mindat).

Localities

The type locality is the Krunkelbach Valley Uranium deposit, Menzenschwand, St Blasien, Waldshut, Freiburg Region, Baden-Württemberg, Germany.

Metauranocircite from Krunkelbach - Image

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