February 23, 1999
New Tanzanite Simulant Headed for Market
A new product that simulates tanzanite is slated to appear on the market by early summer, sources tell Professional Jeweler.
The material, which is manufactured in Russia, has no name yet and is being kept under wraps. According to sources who have seen it, the material is remarkably like high-quality tanzanite in appearance. It's doubly refractive, orthorombic and has a refractive index of 1.67, a specific gravity of 3.2 and a birefringence of 0.036 all properties that are close to those of tanzanite.
What's particularly interesting, sources say, is that the simulant's optical and physical properties do not overlap with those of synthetic corundum or synthetic garnets, both of which are used as tanzanite simulants. The new product may not have a counterpart in nature. Observers say further the material can be separated from natural tanzanite using standard gemological visual techniques or with a filter known as an "aquamarine filter," which allows the examination of large stone parcels.
- by Robert Weldon, G.G.