What is Olshanskyite?
Olshanskyite is a rare hydrated calcium borate from evaporitic and boron-rich environments, often forming pale fibrous or compact aggregates.
Mineralogy and crystal structure
Reference formula: Ca2B5O9(OH)5·4H2O. Olshanskyite is a hydrated triclinic borate with structurally bound water and hydroxyl. Dehydration or alteration can change the material, so the reported formula is an ideal composition. Olshanskyite is classified with borates and has a triclinic crystal system. Typical hardness is 2–3 on the Mohs scale and specific gravity is approximately 2.1–2.3.
Colour, lustre and habit
Typical colours include white, colourless, cream, yellow. The usual acicular, fibrous, massive habit and vitreous, pearly lustre help describe a specimen, but colour alone is not diagnostic.
Formation and notable localities
Olshanskyite forms in or is associated with borate deposits, evaporite basins and late hydrothermal alteration of boron-rich rocks. Important documented localities include Russia, Kazakhstan, Turkey and other borate-bearing regions.
A pale borate shaped by water
Olshanskyite demonstrates that water can be part of a mineral's architecture. Its delicate borate framework forms and survives only within a narrow chemical and thermal window.
Collecting and care
Keep dry and protected from heat; avoid soaking, acids and abrasion.
