Bassetite Locality: Hagendorf South Pegmatite (Cornelia Mine; Hagendorf South Open Cut), Hagendorf , Waidhaus , Vohenstrauß , Oberpfälzer Wald , Upper Palatinate , Bavaria , Germany ( Locality at mindat.org ) Picture width 2 mm. Collection and photograph Christian Rewitzer — Photo: Christian Rewitzer · CC BY-SA 3.0
Bassetite
Bassetite is an IMA-recognized mineral species in the phosphate class, with the chemical formula Fe²⁺(UO₂)₂(PO₄)₂(H₂O)₁₀.
It crystallizes in the monoclinic crystal system (space group P2_1/m).
Key properties: Mohs hardness 2.5; specific gravity 3.4–3.63; Vitreous, bronzy on {010} luster; optically biaxial.
IMA symbol Bas, grandfathered status — known before the IMA’s founding, named in 1915.
A rare secondary mineral found in the oxidized zone of some uranium-bearing hydrothermal mineral deposits.
It is found associated with Uranospathite, torbernite, uraninite, pyrite (Basset mines, England); meta-autunite, torbernite (Arcu su Linnarbu, Italy); saléeite, metanováčekite (Sue mine.
The name refers to the Basset mine group, Cornwall, England, from which it was first described.