Fluorescence Produced by Optical Defects in Diamond: Measurement, Characterization, and Challenges
How variations in UV lamp output can affect observed fluorescence color and intensity.
Iridescence in Metamorphic “Rainbow” Hematite
Analyzes the substructures that cause the intense iridescence observed in “rainbow” hematite from Minas Gerais, Brazil.
The Identification of Blue Diffusion-Treated Sapphires
Blue diffusion-treated sapphires are becoming more prevalent than ever before.
Amethyst from Boudi, Morocco
An introduction to Moroccan amethyst, which features distinctive color zoning and inclusions.
Classifying Emerald Clarity Enhancement at the GIA Gem Trade Laboratory
One of the greatest concerns with emerald filling is the degree of clarity enhancement such treatment represents
Optical Defects in Diamond: A Quick Reference Chart
A simple chart on optical defects in diamond, including those that produce coloration and fluorescence colors.
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.
Reversible Color Modification of Blue Zircon by Long-Wave Ultraviolet Radiation
Determines whether blue zircon, inadvertently altered to brown by exposure to long-wave UV radiation, can be restored to its original color through the use of incandescent light.
Gray-To-Blue-To-Violet Hydrogen-Rich Diamonds from the Argyle Mine, Australia
The Argyle diamond mine is the only known source of type IaB hydrogen- and nitrogen-rich diamonds colored gray to blue to violet.
Gem-Quality Andalusite from Brazil
idely known as a rock-forming mineral, andalusite is not frequently encountered as a gem material.