Volkovskite

minerals

hilgardite

szaibelyite

Formula: KCa4B22O32(OH)10Cl.4H2O
Hydrated borate containing hydroxyl
Specific gravity:
Hardness: 2½
Streak: White
Colour: Colourless, pink; varying from pale to deep orange
Environments

Evaporite deposits

Volkovskite is found in water-insoluble residues from salt domes and potash deposits (Webmin, HOM).

Localities

The two co-type localities are the Clover Hill deposit, Salt Springs evaporite deposit, Hammond Parish, Kings county, New Brunswick, Canada, and the Inder B deposit and salt dome, Inder, Atyrau Region, Kazakhstan.

At the Kazakhstan type locality volkovskite is associated with halite, sylvite, hilgardite, boracite and anhydrite (HOM, R&M 91.5.434-441).

At the Zechstein evaporites at the Boulby mine, Cleveland, England, UK, volkovskite has been found in rosettiform aggregates to 10 cm. When the enclosing sylvite and halite were removed by dissolution, volkovskite was exposed as euhedral bladed crystals to about 1 mm in thickness, coated by powdery hematite. Powder X-ray diffraction investigations revealed other borate minerals including hydroboracite and boracite microcrystals. Szaibélyite forms sprays and aggregates to 1.5 cm intimately associated with volkovskite, boracite, hilgardite and hydroboracite. Hilgardite occurs with volkovskite as blocky microcrystals. Sylvite and halite are common and constitute the soluble groundmass on most specimens (R&M 91-5.434-441).

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