Colored Stones and Pearls
Abstracts of speaker presentations from the “Colored Stones and Pearls” session of GIA’s 2018 International Gemological Symposium.
Abstracts of speaker presentations from the “Gem Characterization” session of GIA’s 2018 International Gemological Symposium.
New Technologies and Techniques
Abstracts of speaker presentations from the “New Technologies and Techniques” session of GIA’s 2018 International Gemological Symposium.
Synthetic Star Sapphires and Rubies Produced by Wiede’s Carbidwerk, Freyung, Germany
Details the process used by Wiede’s Carbidwerk to produce star synthetic corundum from the mid-1950s through the 1970s.
Causes of Iridescence in Natural Quartz
Describes the occurrence of iridescence, and the role of differential etching, in quartz crystals from India’s Jalgaon District.
Bead-Cultured and Non-Bead-Cultured Pearls from Lombok, Indonesia
Documents the retrieval and testing of P. maxima cultured pearls from a Lombok hatchery.
Aurora Iris Agate
An iris agate with a unique growth texture is carved to produce an aurora-like effect.
The Challenges of Cutting a Large Gem Opal Rough
A first-person account of cutting a 3,019 ct piece of white opal to create a 1,040 ct gem with play-of-color across the surface.
Pleochroism in Faceted Gems: An Introduction
Describes the phenomenon of pleochroism and its complex effect on the appearance of colored stones.
Color Phenomena of Blue Amber
Investigates the presence of fluorescence, rather than iridescence, as the cause of color in blue amber from the Dominican Republic and Indonesia.