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Formula: Na6(UO2)(SO4)4(H2O)4
Valence: Na6(U6+O2)(S6+O4)4.4H2O
Hydrated uranyl sulphate, monoclinic paramorph of triclinic
péligotite
Crystal system: Monoclinic
Specific gravity: 2.90 measured, 2.923 calculated for the empirical formula
Hardness: 2½
Streak: Pale yellow-green
Colour: Yellowish green to greenish yellow
Luminescence: Fluoresces bright bluish green under both long wave and short wave UV
Solubility: Easily soluble in water at room temperature, slightly deliquescent
RADIOACTIVE
Environments
Sedimentary environments
Hydrothermal environments
Localities
At the type locality, the Blue Lizard Mine, Red Canyon Mining District, San Juan County, Utah, USA,
klaprothite,
péligotite and ottohahnite
were found together as secondary phases. All three minerals
occur as yellowish-green to greenish-yellow crystals, are brittle with irregular fracture, have Mohs hardness of ∼2½
and exhibit bright bluish-green fluorescence, and all are easily soluble in room-temperature H2O. Only
klaprothite exhibits cleavage, perfect in two directions
(MM 81.4.753-779).
The minerals occur as efflorescent crusts on mine walls, formed by hydration-oxidation weathering of
primary uranium
minerals (mainly uraninite) by acidic solutions from the decomposition of
sulphides. Associated minerals include blödite,
bluelizardite, bobcookite,
epsomite, gypsum,
hexahydrite, konyaite,
plášilite and tamarugite
(HOM).
Klaprothite from the Blue Lizard Mine -
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