Munirite

munirite

vanadium

uraninite

coffinite

Images

Formula: NaV5+O3.1.9H2O
Vanadium oxysalt
Specific gravity: 2.43
Hardness: 1 to 2
Colour: Colourless, white, tinged apple-green
Solubility: Soluble in water
Environments

Sedimentary 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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