A probertite specimen from the Kohnstein quarry near Niedersachswerfen (Nordhausen, Thuringia) is a true rarity for mineral collectors.
This rare calcium-sodium borate (NaCaB₅O₇(OH)₄ ⋅ 3H₂O) is usually found worldwide only in the form of massive nodules or inconspicuous, fibrous aggregates (often from the famous borax deposits in California or Turkey). However, the find at Kohnstein in the 1990s and subsequent years is considered absolutely exceptional by experts, as the mineral crystallized there with completely unexpected clarity in geodes and veins of the massive, often pinkish anhydrite.
This gangue piece is an outstanding specimen of this occurrence. The close-up beautifully illustrates the characteristic parallel-fibrous to columnar texture of the mineral. The very high, perfect cleavage and the typical, slightly silky to glassy luster on the striations are clearly visible. The fact that it is a dense gangue piece does not detract from its value: pieces of this size are extremely rare from the Kohnstein, as extracting the brittle material from the hard anhydrite matrix under hazardous conditions during active mining was an enormous challenge.
A fascinating and historically significant piece of German mineralogical history!
Size: 6.0 x 4.0 x 2.5 cm
Locality: Kohnstein Quarry, Niedersachswerfen, Thuringia, Germany
In modern crystal healing, probertite is considered a rare but highly valued energetic companion, primarily associated with clarity, structure, and mental relief. Its pure white, parallel-fibrous structure is said to act like an energetic light guide, helping to organize jumbled thoughts, sharpen focus, and noticeably strengthen concentration.
At the same time, it is used in lithotherapy as a gentle anti-stress stone. It supports people in chaotic or overwhelming phases of life in releasing inner pressure and emotional baggage, making it easier to make rational decisions again.
