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Micro-Features of Ruby
Inclusions in Natural, Synthetic and Treated Ruby

Provides a visual guide to the internal features of natural, synthetic and treated rubies.

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Four types of heated Baltic amber
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.

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Faceted CVD Synthetic Diamonds
CVD Synthetic Diamonds from Gemesis Corp

An examination of the gemmological and spectroscopic properties of CVD synthetic diamonds from Gemesis Corp.

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Coloured Diamonds in the Aurora Butterfly of Peace Collection
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.

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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.

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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.

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A Gemmological Study of a Collection of Chameleon Diamonds

Chameleon diamonds are among the rarest of gem diamonds.

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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.

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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.

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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.

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