Tanzanite from Tanzania

A tanzanite crystal from the Merelani Hills, Tanzania, prismatically grown with a slender columnar shape and deep blue hue. The tip clearly shows the pyramidal termination typical of well-crystallized material from this deposit.

Tanzanite is the vanadium-bearing gem variety of zoisite. The blue-violet coloration is developed through heat treatment from the original yellowish-brown rough material, a procedure accepted in gemmology standards that releases the latent pleochroic coloration.

Pleochroism, the direction-dependent play of colors, is the optical signature of tanzanite. Depending on the viewing angle, the stone appears blue, violet, or reddish-brown. Cutting workshops therefore orient themselves to the axis that shows the most intense blue.

The Merelani Hills are the only known deposit for tanzanite worldwide. Tiffany & Co. introduced the material to international trade in 1967 under the name Tanzanite. Geological forecasts predict the deposit will be exhausted in 20 to 30 years.

A collector's item with gemmological distinctiveness and finite availability, suitable for collectors who focus on rare gemstone species.