Outstanding beige sharp perfect crystals of the very rare mineral berborite in a matrix of natrolite. From: Saga 1 Quarry, Porsgrunn, Telemark, Norway. — Photo: David Hospital · CC BY-SA 4.0
Berborite
A colorless, transparent beryllium borate with a vitreous luster.
Intro adapted from Wikipedia (CC BY-SA).
Berborite is an IMA-recognized mineral species in the borate class, with the chemical formula Be₂(BO₃)(OH)·H₂O.
It crystallizes in the hexagonal crystal system (space group P321).
Key properties: Mohs hardness 3; specific gravity 2.03–2.06; Vitreous luster; refractive index 1.533; optically uniaxial.
IMA symbol Bbo, IMA status: approved, named in 1967.
Found in serpentinized dolostone in association with W–Sr–B–Be-bearing skarns (Pitkäranta district, Russia); in vugs with natrolite (Saga quarry, Norway).
It is found associated with Hambergite, schoenfliesite, helvite, apatite, cassiterite, fluorite, calcite, dolomite, magnetite, sphalerite, vesuvianite, chondrodite, diopside, smithsonite.
The name refers to BERyllium and BORate in the composition.