Volkovskite in Hilgardite

Volkovskite is a very rare borate typically found in salt domes or potash deposits. The Boulby Mine is the world’s only commercial polyhalite mine, located in North Yorkshire, England, and has been extracting potash since the 1970s. This specimen comes from a small find which was considered best of species.

Locality: Boulby Potash Mine, Loftus, North Yorkshire England

Composition: hydrated potassium calcium borate on calcium chloroborate