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Molybdate

Tengchongite

Ca(UO₂)₆(MoO₄OH)₂O₂(OH)₄·9H₂O
Hardness2–2.5
Crystal systemOrthorhombic
ClassMolybdate
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Tengchongite specimen

A yellow single crystal of the extremely rare U-Mo mineral tengchongite from one of only three known localties worldwide (Oktyabr'skoe Deposit, Krasnokamensk, Chitinskaya Oblast, Zabaykalsky Krai, Russian Federation). Ex.Dr.I.Pekov specimen and analyzed by him. — Photo: David Hospital · CC BY-SA 4.0

Tengchongite

Tengchongite is an IMA-recognized mineral species in the molybdate class, with the chemical formula Ca(UO₂)₆(MoO₄OH)₂O₂(OH)₄·9H₂O.

It crystallizes in the orthorhombic crystal system (space group C222_1).

Key properties: Mohs hardness 2–2.5; specific gravity 4.25; Vitreous luster; optically biaxial.

IMA symbol Tcg, IMA status: approved, named in 1984.

Found in the oxidized portions of a uranium deposit in migmatite and gneiss.

It is found associated with Studtite, calcurmolite.

The name refers to Tengchong Co., China, where the first specimens were found.

Index entry. This entry combines official IMA/RRUFF species data with published physical-property data — a full written entry hasn’t been published yet. Browse more T minerals or help write this entry.