Locality: No. 3 Mine, Huanggang Fe-Sn deposit (Huanggangliang Mine; Huanggang Mine), Hexigten Banner (Keshiketeng Co.), Ulanhad League (Chifeng Prefecture), Inner Mongolia Autonomous Region, China 2.9 cm. From a 2010 pocket. The small white crystals were determined to be cahnite by Paul Pohwat of the Smithsonian Institution – the first new locality for the species in 100 years. Rob Lavinsky Collection. Joe Budd photo. — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Borcarite
Borcarite is an IMA-recognized mineral species in the borate class, with the chemical formula Ca₄MgB₄O₆(CO₃)₂(OH)₆.
It crystallizes in the monoclinic crystal system (space group C2/m).
Key properties: Mohs hardness 4–4.5; specific gravity 2.56–2.77; Vitreous, slightly pearly on cleavages luster; optically biaxial.
IMA symbol Bcr, IMA status: approved, named in 1965.
Found in kotoite marbles, near the contact with granodiorite (Snezhnoye deposit, Russia); a rare secondary mineral probably formed by reaction of late hydrothermal fluids with brucite (Fuka, Japan).
It is found associated with Szaibélyite, uralborite, sibirskite, kotoite, magnetite, spinel, calcite (Snezhnoye deposit, Russia); olshanskyite, bultfonteinite, takedaite, calcite (Fuka.
The name refers to BORate and CARbonate in the composition.