Optical Effects of Phenomenal Cabochons
Learn how the structure, inclusions and properties of some gemstones interact with light to create unusual visual effects.
Spring 1991 G&G Lab Notes
This section, from the Spring 1991 issue of Gems & Gemology, is a compilation of interesting finds from GIA’s laboratories.
Sri Lanka: The Gem Island
An overview of the many types of gem-quality material, and its inclusions, currently found in Sri Lanka.