Pandoraite-Ba
Pandoraite-Ba is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula BaV⁴⁺₅V⁵⁺₂O₁₆·3H₂O.
It crystallizes in the monoclinic crystal system (space group P2). It is a member of the Pandoraite structural group.
Key properties: Mohs hardness 2.5; specific gravity 3.24; Light greenish blue streak; Vitreous luster; optically uniaxial.
IMA symbol Pdo-Ba, IMA status: approved, named in 2018.
Deposited from solutions rich in U and V where they encountered pockets of strongly reducing solutions developed around accumulations of carbonaceous plant material.
It is found associated with Carnotite, a Ba-Fe-V-bearing member of the alunite supergroup.
The name refers to the mine where it was discovered, and a suffix indicates the dominant interlayer cation.