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Formula: Ba(UO2)2W2O8(OH)2.H2O
Hydrated wolframate, barium- and
uranyl- bearing mineral
Crystal system: Monoclinic
Specific gravity: >4.03 measured, 4.27 calculated
Hardness: 2
Streak: Yellow
Colour: Yellow, orange, brown, blackish
Solubility: Decolourised but not dissolved by either 1:1 nitric acid or 1:1 sulphuric acid, dissolved by cold 1:1
hydrochloric acid, and the reaction is accelerated upon warming. A yellow residue remains upon evaporation.
Environments
Plutonic igneous environments
Hydrothermal environments
Localities
There are two co-type Localities, the Clara Mine, Oberwolfach, Ortenaukreis, Freiburg Region, Baden-Württemberg,
Germany and the Krunkelbach Valley Uranium deposit, Menzenschwand, St Blasien, Waldshut, Freiburg Region,
Baden-Württemberg, Germany. At the type localities uranotungstite forms crusts on
quartz, metauranocircite
and metaheinrichite. Other associated minerals include
bergenite,
metatorbernite,
metazeunerite and
schoepite. The uranotungstite occurs as spherulitic aggregates up
to 0.3 mm across.
The mineral is claimed to be the first uranyl tungstate found naturally
(AM 71.1547).
Uranotungstite from the Clara Mine -
Image
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