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Formula: NaV5+O3.1.9H2O
Vanadate
Crystal System: Monoclinic
Specific gravity: 2.43 measured, 2.44 calculated
Hardness: 1 to 2
Colour: Colourless, white, tinged apple-green
Solubility: Soluble in water
Environments
Munirite may dehydrate to metamunirite (Mindat).
Localities
At the type locality, the Bhimber District, Azad Jammu and Kashmir, Pakistan, munirite was collected from
sandstone. It crystallises as radiating fibrous aggregates on outcrops
and on the walls of exploratory trenches. A variety of secondary
uranium minerals have been described from this sandstone, including
carnotite, tyuyamunite,
metatyuyamunite, bayleyite,
andersonite and uranophane.
These are considered to be products of the oxidation of uraninite from
uraninite-coffinite assemblages
in unaltered sandstone. Breakdown of
vanadium bearing hexavalent uranium minerals and consequent leaching of
highly soluble hexavalent uranium may have caused a local enrichment of
vanadium and subsequent precipitation of munirite through evaporation
of groundwater
(MM 47.391-392).
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