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Formula: KCa4B22O32(OH)10Cl.4H2O
Hydrated borate containing hydroxyl
Crystal System: Triclinic
Specific gravity: 2.27 measured, 2.28 calculated
Hardness: 2½
Streak: White
Colour: Colourless, pink; varying from pale to deep orange
Environments
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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