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Formula: (NH4)2(Na2☐)[(UO2)2(SO4)3(H2O)]2.7H2O
Sulphate, uranyl mineral
Crystal System: Tetragonal
Specific gravity: 3.465 calculated
Hardness: 2½
Streak: Very pale green-yellow
Colour: Light green
Luminescence: Strong green fluorescence under 405 nm UV
Solubility: Soluble in water
RADIOACTIVE
Environments
Sedimentary environments
Hydrothermal environments
Libbyite is a new mineral, approved in 2022 and to date (November 2023) reported only from the
type locality.
Localities
At the type locality, the Blue Lizard Mine, Red Canyon Mining District, San Juan County, Utah, USA,
libbyite occurs as tightly intergrown aggregates of light green–yellow equant crystals in a
secondary assemblage with
bobcookite, coquimbite,
halotrichite,
metavoltine,
rhomboclase, römerite,
tamarugite, voltaite and
zincorietveldite. The streak is very pale green yellow and
the fluorescence is strong green under 405 nm ultraviolet light. Crystals are transparent with vitreous lustre The tenacity is brittle, the Mohs hardness is ~2½, the fracture is curved.
(MM 87.5.767-772).
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