Umohoite Field of view: 4 mm Locality: Rabejac Est, Le Puech, Lodève, Hérault, Occitanie, France — Photo: Leon Hupperichs · CC BY-SA 3.0
Umohoite
A uranyl molybdate — its name literally spells its composition: U-Mo-H₂O.
Intro adapted from Wikipedia (CC BY-SA).
Umohoite is an IMA-recognized mineral species in the molybdate class, with the chemical formula (UO₂)(MoO₄)·2H₂O.
It crystallizes in the triclinic crystal system (space group P2_1/c).
Key properties: specific gravity 4.53–4.66; Vitreous luster; optically biaxial.
IMA symbol Umo, grandfathered status — known before the IMA’s founding, named in 1953.
A rare secondary mineral, typically in sediment-hosted uranium-bearing deposits, formed in the oxidation zone above the water table.
It is found associated with Uraninite, ilsemannite, jordisite, iriginite, schoepite, uranophane, rutherfordine, calcurmolite, fluorite, pyrite, gypsum, quartz.
The name refers to Uranium, MOlybdenum, Hydrogen, and Oxygen in the composition.