Synthetic Sapphire and Synthetic Spinel Doublets
Unusual doublets created from two different synthetics are revealed at the Carlsbad laboratory.
Spring 1991 G&G Lab Notes
This section, from the Spring 1991 issue of Gems & Gemmology, is a compilation of interesting finds from GIA’s laboratories.
Yellow Synthetic Sapphire Coloured by Trapped-Hole Mechanism
A combination of trace-element analysis and UV-visible spectroscopy clearly indicated that the yellow colour originated from the much more effective chromophore known as “trapped holes” associated with the trace amount of Mg and Cr in this stone.