Phosphowalpurgite

phosphowalpurgite

smrkovecite

hechtsbergite

petitjeanite

Images

Formula: (U6+O2)Bi4O4(PO4).2H2O
Hydrated phosphate, uranyl mineral, walpurgite group, bismuth-bearing mineral
Crystal System: Triclinic
Specific gravity: 6.36 calculated for the empirical formula
Streak: Light brown
Colour: Brownish grey
Luminescence: Nonfluorescent both under long wave and under short wave UV
Very strongly RADIOACTIVE
Environments

Metamorphic environments
Hydrothermal environments

Phosphowalpurgite is a secondary mineral formed by weathering of primary bismuth and uraninite in hydrothermal quartz veins (HOM).

Localities

At the type locality, Smrkovec, Březová, Sokolov District, Karlovy Vary Region, Czech Republic, veins of hydrothermal ore are located in a fault zone between a granite body and the surrounding metamorphic rocks. This rock complex includes chloritewhite mica phyllites, metamorphosed along the granite contact into two-mica gneisses and massive hornfels with sillimanite, andalusite and garnet. Phosphorus-rich rocks also occur in this complex. It appears that the mineralisation is related to thin hydrothermal quartz veins and alteration zones along those veins where impregnations of bismuth, bismutite and bismutoferrite occur.
Primary mineralisation is represented by irregularly disseminated aggregates of ore minerals, especially bismuth, galena, silver-bearing sulphides, nickel-cobalt arsenides and uraninite, enclosed in a quartz gangue. Grains of massive grey sillénite, up to several cm in size and probably of primary origin were identified sporadically.
Secondary minerals include metatorbernite, autunite, zippeite, retgersite, atelestite, hechtsbergite, smrkovecite, preisingerite, petitjeanite, eulytine, bismutite, bismutoferrite, mixite, pucherite and (PO4)-rich walpurgite.
Phosphowalpurgite occurs as small clusters of irregular crystals, up to 1 cm in size, within small fissures and cavities in the quartz gangue. Subhedral to euhedral tabular crystals do not exceed 1 mm in size and average 0.1 to 0.3 mm (CM 42.4.963-972).

Phosphowalpurgite from Smrkovec - Image

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