Zoisite (Tanzanite)

A superb bi-colour tanzanite crystal from the world-famous Merelani Hills of Tanzania, weighing 6.6 grams. The crystal displays excellent transparency and lustre. Viewed from different angles, the crystal exhibits the  pleochroism for which tanzanite is renowned, shifting from blue to violet tones as it is rotated. The crystal retains its natural yellow coloration in the upper crystal zone, indicating that it has not been heat treated. This is a noteworthy feature, as most tanzanite on the market has been heated to enhance its blue-violet colour.

The crystal displays classic tapered habit characteristic of tanzanite, with well-defined striated prism faces and a sharp double chisel-shaped termination. It is cleaved at the base and back where it was removed from the wall and shows minor contact marks along the sides, neither of which significantly detract from its overall appearance when viewed from the front. Transparent, lustrous, and well formed, this specimen would make an outstanding miniature display piece.

Tanzanite is the gem variety of zoisite and is found exclusively in the Merelani Hills near Arusha, Tanzania, making it one of the most geographically restricted gemstones in the world. The mineral owes its remarkable blue and violet colours to traces of vanadium within its crystal structure. Unheated crystals retaining their original yellow, blue, and purple colour zoning are far less common than their heat-treated counterparts and offer a fascinating glimpse into the mineral's natural beauty. An eye-catching and highly collectible example of this famous gemstone mineral.