Vanuralite

vanuralite

francevillite

duttonite

metavanuralite

Images

Formula IMA: Al(U6+O2)2(V5+O4)2(OH).8.5H2O
The formula of vanuralite and related minerals is commonly mistakenly written as to be containing VO4 groups. Since the structure does not contain any of them, but V2O8 dimers (pairs of edge-sharing VO5 tetragonal pyramids), the formula has to be written as
Al[(UO2)2V2O8(OH)].11H2O.
The real H2O content can be significantly lower (8.5H2O according to structure determination of Plášil, 2017) (Mindat).
Valence: Al[(U6+O2)2V5+2Osub>8(OH)].11H2O
Hydrated uranyl vanadate, carnotite group
Crystal System: Monoclinic
Specific gravity: 3.62 measured, 3.16 calculated
Hardness: 2
Colour: Citron-yellow, canary-yellow, pale yellow
RADIOACTIVE
Environments

Sedimentary environments
Hydrothermal environments

Localities

At the type locality, the Mounana Mine, Mounana, Léboumbi-Leyou Department, Haut-Ogooué Province, Gabon, vanuralite occurs in the oxidised zone of the lead-bearing U–V deposit. Associated minerals include metavanuralite, francevillite, curienite, duttonite, chervetite, brackebuschite, mottramite, carnotite, dewindtite, torbernite, uranopilite, johannite and kasolite (HOM).
Vanuralite from the Mounana Mine - Image

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