Borcarite

borcarite

szaibelyite

kotoite

uralborite

Images

Formula: Ca4MgB4O6(CO3)2(OH)6
Compound borate
Crystal System: Monoclinic
Specific gravity: 2.77 measured, 2.765 calculated
Hardness: 4
Streak: White
Colour: Greenish-blue to bluish green, nearly colourless
Environments

Metamorphic environments
Hydrothermal environments

Localities

At the Fuka mine, Fuka, Bitchū, Takahashi City, Okayama Prefecture, Japan, borcarite is a rare secondary mineral probably formed by reaction of late hydrothermal fluids with brucite. Associated minerals include olshanskyite, bultfonteinite, takedaite and calcite (HOM).

At the Type Locality, the Snezhnoe B ore occurrence, Izvestkovyi Stream, Titovskoe B deposit, Tas-Khayakhtakh Range, Dogdo River Basin, Polar Yakutia, Sakha Republic, Russia, borcarite occurs in kotoite marble, formed in dolostone near the contact with granodiorite. The borcarite forms dense masses up to 0.5 m in diameter and as veins in kotoite marble and in ludwigite-szaibélyite-magnetite rock. It contains inclusions of szaibélyite, calcite, serpentine, magnetite and spinel (AM 50.2097). Other associated minerals include uralborite, sibirskite and kotoite (HOM).

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