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Formula: Na[(UO2)8O3(OH)11].10H2O
Hydrated uranyl hydroxide
Crystal System: Orthorhombic
Specific gravity: 5.044 calculated for the empirical formula and 5.036 calculated for the ideal formula
Hardness: 2
Streak: Pale yellow
Colour: Yellow
Luminescence: Yellow fluorescence under 365 nm UV
Environments
Sedimentary environments
Hydrothermal environments
Bobfinchite is a new mineral, approved in 2021 and to date (September 2024) reported only from the
type locality.
Localities
At the type locality, the Burro Mine, Slick Rock Mining District, San Miguel County, Colorado, USA,
bobfinchite occurs in the uranium deposit as an oxidation product of
uraninite on asphaltite
matrix in intimate association with gypsum,
natrozippeite,
metaschoepite and
uranopilite. Bobfinchite crystals are transparent to
translucent, yellow, lozenge-shaped disks up to 0.3 mm wide
(AM 109.7.1266-1274).
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