Gem of the Week: Tanzanite

An extremely rare tanzanite brooch designed by
Jean Schlumberger for Tiffany & Co.
Lang Antique and Estate Jewelry

Discovered in a Tanzanian mine in 1967, Tanzanite is a variant of the mineral zoisite. At first, incorrectly identified as a host of other gemstones, Tanzanite was finally correctly classified when geologist John Saul sent a sample of the stone to his father, Hyman Saul. The elder Saul was vice president of Saks Fifth Avenue and brought the stone to the Gemological Institute of America for identification.


Tiffany and Co. learned of this newly discovered gem and wished to create a line of jewelry featuring the brilliant stone whose colors ranged from blue to red to violet depending on the light. Executives at Tiffany and Co., however, weren’t too keen on its name, blue zoisite, thinking that it could be mistaken for the words, “Blue Suicide.” They renamed the gem, “Tanzanite” for the purposes of marketing, and the name was officially adopted for this unusual and rare stone.

Tanzanite is mainly found in Tanzania, though some veins have been found in other areas. The rarity of natural tanzanite makes it extremely valuable. This is one stone whose value is not affected by being color enhanced or treated. All tanzanite is heat treated to enhance the blue color in the naturally red-purple natural stone. Since it is universally heat-treated, the value is not diminished by human interference.

Tanzanite was recently adopted as one of the primary birthstones for December.