1 September 2006
A brief look at the famous emerald and alexandrite from Russia's Ural Mountain mines.
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1 July 2005
Fiber-optic lighting is one of the most useful form of lighting in the gemological laboratory. With it, we are able to see inclusions that would otherwise be invisible.
1 October 2005
A discussion of how inclusion patterns mimic crystallographic symmetry in ruby and sapphire.
1 June 1990
Surface ('bulk') diffusion-treated corundums (SDTCs) created a stir in the Bangkok market in 1990. This article looks at the original patents and continues through the so-called "Deep Diffusion" treatment. Identification methods are discussed, as well as the backroom politics of disclosure. At the end is a quick-reference table summarizing key identifying features of all types of natural, treated and synthetic corundums.
1 August 1997
A description of the fracture healing of Mong Hsu ruby, along with the problems this has created in the gem trade.
1 June 2005
Gübelin, Eduard J. & Koivula, John I. (2005) Photoatlas of Inclusions in Gemstones, Volume 2. Opinio Publishers, Basel, Switzerland, 830 pp. ISBN 978-3855040957
1 January 2008
Gübelin, Eduard J. & Koivula, John I. (2005) Photoatlas of Inclusions in Gemstones, Volume 3. Opinio Publishers, Basel, Switzerland, 672 pp. ISBN 3-03999-047-4
1 January 1997
Inclusions are among the most important features for identifying ruby and sapphire. This is the chapter on ruby and sapphire inclusions from Richard Hughes' 1997 book, Ruby & Sapphire.
1 May 2005
A discussion of rutile silk in corundum (ruby & sapphire) and its use in detecting artificial heat treatment. Careful examination of these "silk" inclusions can provide vital clues to unmask heated gems.
1 September 2005
Virtually all gemologists are aware of the curved growth lines and gas bubbles in Verneuil (flame-fusion) synthetic corundum, but few understand exactly why they occur and how they are distributed in these stones. This article clarifies these important identifying features.
1 June 2005
The examination of a yellow sapphire provides a lesson in the power of gemological microscopy.