Oldsite

oldsite

stanleyite

mathesiusite

romerite

Images

Formula: K2Fe2+[(UO2)(SO4)2]2(H2O)8
Uranyl sulphate
Crystal System: Orthorhombic
Specific gravity: 3.31 measured, 3.298 calculated for the empirical formula and 3.330 for the ideal formula
Streak: Very pale yellow
Colour: Yellow
Luminescence: Not fluorescent under UV
RADIOACTIVE
Environments

Hydrothermal environments

Oldsite is a new mineral, approved in 2021 and to date (April 2023) reported only from the type locality.

Localities

At the type locality, the North Mesa Mine Group, Temple Mountain Mining District, Emery County, Utah, USA, oldsite is found as a secondary mineral occurring with alum-(K), halotrichite, metavoltine, quartz, römerite, stanleyite, sulphur, szomolnokite and mathesiusite. It forms rectangular blades reaching ~0.3 mm in length. Crystals are yellow in colour, transparent with a vitreous lustre. Crystals are brittle with irregular, splintery fracture (MM 87.1.151-159).

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