Fall 2015 G&G: Trapiche Emeralds, Synthetic Diamonds and a Large Diamond Source
G&G Brief presents an overview of the content of the Fall 2015 issue of Gems & Gemology.
Optical Defects in Diamond: A Quick Reference Chart
A simple chart on optical defects in diamond, including those that produce coloration and fluorescence colors.
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.
Calcium Fluoride Coating Found on 13 "Fancy" Pink Diamonds
Recent lab examination reveals that traditional treatments such as calcium fluoride coating are still prevalent in the trade, and great care must be taken to identify them.
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.
Detection of Treatment in Two Unusual Green Diamonds
A pair of sharp absorption bands in the near-infrared region, referred to as H1b and H1c, have been detected in one (and the H1b band in the other) of two green diamonds known to have been treated.
The Identification of Artificial Coloration in Diamond
The source of color in some diamonds, particularly fluorescent green and some yellow stones, can be very difficult to identify despite increasing knowledge about the radiation-related bands seen in the visible spectra of diamonds.
Characterization and Grading of Natural-Color Yellow Diamonds
A large number of natural-color yellow diamonds are analyzed using grading and appearance aspects among other characteristics to clarify the differences between them and the light yellow diamonds associated with GIA's D-to-Z color grading scale.
Treated-Color Pink-To-Red Diamonds from Lucent Diamonds Inc.
Using a multi-step process, Lucent Diamonds has developed a new treatment process for certain natural diamonds that creates colors from pink-purple through red to orangy brown.
Lab-Grown Colored Diamonds from Chatham Created Gems
This article compares some of Chatham Created Gems’ synthetic colored diamonds to natural diamonds and explains the results.