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Formula: Na4(UO2)(SO4)3.3H2O
Valence: Na4(U6+O2)(S6+O4)3.3H2O
Hydrated sulphate, uranyl mineral
Crystal System: Orthorhombic
Specific gravity: 3.23 measured, 3.313 calculated
Hardness: 2½
Streak: White
Colour: Pale greenish yellow
Luminescence: Bright greenish white fluorescence under UV
Solubility: Easily soluble in water at room temperature
RADIOACTIVE
Environments
Sedimentary environments
Hydrothermal environments
Fermiite is a relatively new mineral, approved in 2014 and to date (December 2025) reported only from the
Red Canyon mining district.
Localities
At the type locality, the Blue Lizard Mine, Red Canyon Mining District, San Juan County, Utah, USA, fermiite
occurs as a secondary mineral from post-mining oxidation of
primary uraninite,
pyrite, chalcopyrite,
bornite and covellite, deposited as
replacement of wood and other organic material and as disseminations in the enclosing
sandstone. Associated minerals include
oppenheimerite, blödite,
bluelizardite,
chalcanthite, epsomite,
gypsum, hexahydrite,
kröhnkite, manganoblödite,
sideronatrite, tamarugite
and wetherillite
(HOM).
Fermiite from the Blue Lizard Mine -
Image
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