Some Tanzanite Imitations

摘要

Since at least 1995, various materials have been manufactured to imitate tanzanite in the gem trade. These include two glasses, two different YAGs (yttrium aluminum garnet), and a synthetic corundum. These imitation tanzanites can be readily separated from the natural gem by standard gemological tests, such as refractive indices, optical character, specific gravity, UV-visible spectra, fluorescence, and the presence or absence of pleochroism. The identifications were confirmed by chemical analysis and Raman spectroscopy.