A group of four transparent anhydrite crystals is perched across the top of an aggregate of probertite. These anhydrites are incredible for the species – clear, sharp and lustrous. The crystal at the upper left is the star – it sits up enough over the probertite that the light plays inside it, and it has the nice pale lilac colour. It is attached/parallel growth with an adjacent crystal, and the width of these two together is 1.4 cm.
No damage to the upper left crystal, minor nicks on a couple of the others, very small in the context of the piece. There are other sharp anhydrite crystals lower on the piece – some are complete, some are incomplete.
The upper left crystal is a gem – anhydrite crystals don’t get much better than this!
About these Anhydrite/Probertite Specimens
These excellent specimens of anhydrite and probertite were found in a pocket at the Kohnstein Quarry, Niedersachswerfen, Nordhausen, Harz, Thuringia, Germany. The anhydrite crystals are amazing – euhedral, very pale lilac, translucent to transparent. I am told that although they are encountered at this locality once in a while, this is only the third time in the last 30 years, so it is not a common occurrence.
Anhydrite is one of those common minerals that is incredibly hard to obtain in display specimens, other than the relatively common light blue Mexican anhydrite fans. Euhedral, well developed crystals of any decent size are rare.
Probertite is a relatively rare borate mineral that occurs as transparent, colourless, heavily striated, lustrous crystals. Atother world localities it usually occurs as radiating aggregates of acicular or columnar crystals, coarser crystal aggregates are uncommon and euhedral terminated crystals much more so.