A single crystal of the extremely rare Be arsenate mineral bearsite from the TL in Kazakhstan (Bota-Burum Uranium Deposit, Alakol, Almaty Province, Kazakhstan) and only one of the two known localities worldwide. Ex Vandenbroucke Museum collection from Waregem, Belgium. — Photo: David Hospital · CC BY 4.0
Bearsite
Bearsite is an IMA-recognized mineral species in the arsenate class, with the chemical formula Be₂(AsO₄)(OH)·4H₂O.
It crystallizes in the monoclinic crystal system (space group P2_1/a).
Key properties: specific gravity 2; optically biaxial.
IMA symbol Bea, IMA status: approved, named in 1962.
Found as a secondary mineral developed during the oxidation of an arsenic-bearing metal sulfide deposit in association with a felsite porphyry containing beryl.
It is found associated with Pharmacosiderite, arseniosiderite, scorodite–mansfieldite, conichalcite, tyrolite, sodium uranospinite, metazeunerite, arsenopyrite, molybdenite, galena.
The name refers to BEryllium and ARSenic in the composition.