White crystals of the rare calcium borate mineral calciborite from the type locality in Russia (Novofrolovskoye Deposit, Turjinsk, Turya River, Krasnotur'insk, Sverdlovsk Oblast, Russian Federation) and only one of the two known localities worldwide. — Photo: David Hospital · CC BY-SA 4.0
Calciborite
A rare calcium borate described in 1955 from a copper-boron deposit in Russia's Northern Urals.
Intro adapted from Wikipedia (CC BY-SA).
Calciborite is an IMA-recognized mineral species in the borate class, with the chemical formula CaB₂O₄.
It crystallizes in the orthorhombic crystal system (space group Pccn).
Key properties: Mohs hardness 3.5; specific gravity 2.878; refractive index 1.64; optically biaxial.
IMA symbol Cbo, grandfathered status — known before the IMA’s founding, named in 1956.
From drillcore into a contact metasomatized limestone near a quartz diorite intrusion in association with a copper deposit in skarn.
It is found associated with Sibirskite, calcite, dolomite, garnet, magnetite, pyroxene.
The name refers to its essential chemical components: CALCIum and BORon.