The Family Tree: Tsavorite & Tanzanite

Green Tsavorite Garnet with Violet Tanzanite (Zoisite) on the outer edge (Photo: B. Olivier). Destruction of the Tsavorite to form Tanzanite.

This year marks the 50th Anniversary of two of the most beautiful gemstones in our industry. The first discovery of green Grossular Garnet and Tanzanite, both took place in 1967 in Tanzania. Tanzanite was named in 1968. Only after the discovery of the green Grossular Garnet in Kenya, was the gemstone named Tsavorite in 1973. Both of these gemstones were named after the locations they were found by Henry Platt, the president of Tiffany & Co.

Most people know this. But how many people know that Tanzanite was created by the recrystallization of Tsavorite? Simply put, Tanzanite was created by the destruction of Tsavorite.

As vanadium is already present in the green grossular garnet (Tsavorite), the equation can be written as:

3 tsavorite + H2O + 5CO2  -  2 tanzanite + 3 quartz + 5 calcite*

which reads: Tsavorite and High Pressure Fluids resulted in Tanzanite & Quartz & Calcite

* PhD dissertation of B.Olivier (University of Stellenbosch, RSA, 2006)