Inclusions in Natural, Synthetic and Treated Ruby
Provides a visual guide to the internal features of natural, synthetic and treated rubies.
Experimental Studies on the Heat Treatment of Baltic Amber
Amber samples were heat-treated, using various procedures and parameters, in an effort to reproduce materials found in the jewellery market.
CVD Synthetic Diamonds from Gemesis Corp
An examination of the gemmological and spectroscopic properties of CVD synthetic diamonds from Gemesis Corp.
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.
A History of Diamond Treatments
Modern gemmologists and diamantaires are faced with a broad spectrum of colour and clarity treatments ranging from the simple to the highly sophisticated.
Coated Pink Diamond — A Cautionary Tale
The Diamond Trading Company (DTC) Research Centre had the opportunity to examine a diamond that, on submission to a commercial gem laboratory, turned out to be a coated pink diamond.
A Gemmological Study of a Collection of Chameleon Diamonds
Chameleon diamonds are among the rarest of gem diamonds.
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.
An Updated Chart on the Characteristics of HPHT-Grown Synthetic Diamonds
A new chart, supplementing the one published in the Winter 1995 issue of Gems & Gemmology, summarises the features of both as-grown (“non-modified”) and treated (“modified”) synthetic diamonds currently in the gem market.
Beryllium Diffusion of Ruby and Sapphire
The heat treatment of corundum involving lattice diffusion of beryllium (Be) at temperatures over 1800°C has become a major issue in the gem trade.