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Formula: Al(UO2)2(AsO4)2F.20H2O
Hydrated arsenate, uranyl mineral
Crystal System: Orthorhombic
Specific gravity: 2.54 calculated
Hardness: 2
Streak: White
Colour: Pale yellow
Luminescence: Weak greenish fluorescence under short wave UV
Solubility: Readily partially dehydrates in air
Common impurities: P
RADIOACTIVE
Environments
Sedimentary environments
Hydrothermal environments
Arsenuranospathite occurs very rarely as a secondary
mineral in uranium deposits. Associated minerals include
zeunerite, uranophane,
studtite, uranospinite,
ianthinite,
metakirchheimerite,
uranocircite–heinrichite,
baryte and limonite
(HOM).
Localities
The type locality is the Sophia Mine, Böckelsbach valley, Wittichen, Schenkenzell, Rottweil, Freiburg Region,
Baden-Württemberg, Germany.
At the Krunkelbach Valley Uranium deposit, Menzenschwand, St Blasien, Waldshut, Freiburg Region, Baden-Württemberg,
Germany, arsenuranospathite was found among the
secondary minerals of the
uranium deposit in crusts on baryte.
It is associated with limonite and
secondary uranium
minerals, such as zeunerite, mixed crystals of the
uranocircite-heinrichite
series, uranophane and
studtite. The arsenuranospathite crusts are composed of minute
tabular crystals, of maximum length about 0.3 mm. Almost a needle-like habit results if the elongation is pronounced
(MM 42.117-128).
Arsenuranospathite from the Krunkelbach
Valley uranium deposit - Image
At the Zimná Voda uranium occurrence, Prakovce, Gelnica District, Košice Region, Slovakia, assemblages of
supergene minerals occur in hydrothermal REE–U–Au
quartz-vein mineralisation. Heterogeneous
uranyl arsenates and minor
phosphates of the autunite group
(nováčekite, kahlerite,
threadgoldite, autunite,
arsenuranospathite and chistyakovaite) together with
scorodite and Sb–Bi-rich
philipsbornite–segnitite
series minerals formed by oxidising fluids during decomposition and leaching of
primary hypogene
uraninite, brannerite and
base-metal sulphides and sulphosalts. A progressive change of pH from acidic to near-neutral due to the gradual
consumption of sulphides resulted in the formation of late
phosphuranylite,
pharmacosiderite and
arseniosiderite. Goethite
and other Fe oxides represent the latest hydrous ferric mineral phases and were formed after most of the As was
already fixed in Fe arsenates. Antimony and
bismuth were taken up only into
philipsbornite–segnitite
and suggest unusual conditions during this process
(MM 87.6.849–865).
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