Uraninite

Uraninite
General
CategoryMineral
Chemical formulaUranium dioxide or uranium(IV) oxide (UO2)
Identification
ColorBlack or brownish
Crystal habitMassive, botryoidal, granular. Crystals uncommon.
Crystal systemIsometric
CleavageIndistinct
FractureConchoidal to uneven
Mohs scale hardness5 - 6
LusterSubmetallic, greasy
StreakSame as colour, black or brownish
Specific gravity7.8 - 10
Refractive indexOpaque
PleochroismNone
SolubilitySoluble in sulfuric, nitric, and hydrofluoric acids.
Major varieties
PitchblendeMassive


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