Optical defects in diamond: a quick reference chart
A simple chart of optical defects in diamond, including those that produce colouration and fluorescence colours.
Grey-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 coloured grey to blue to violet.
The “Type” Classification System of Diamonds and Its Importance in Gemmology
Knowledge of type allows gemmologists to better evaluate if a diamond might be treated or synthetic, and whether it should be sent to a laboratory for testing.
Treated-Colour 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 colours from pink-purple to red to orangey brown.
Gemesis Laboratory-Created Diamonds
High-quality synthetic diamonds created by the Gemesis Corp. are examined and their gemmological properties are explicated.
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.
Lab-Grown Coloured Diamonds from Chatham Created Gems
This article compares some of Chatham Created Gems’ synthetic coloured diamonds to natural diamonds and explains the results.
Characterisation and Grading of Natural-Colour Yellow Diamonds
A large number of natural-colour yellow diamonds are analysed 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 colour grading scale.
The Identification of Artificial Colouration in Diamond
The source of colour 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.