International School of Gemology

The International School of Gemology (ISG), founded in 2004 by Robert James FGA, GG, started as an Allied Gem Tutorial centre for the Gemmological Association of Great Britain. It is now a completely independent institution which offers various courses in gemology.
Controversy
In an article in the June 2009 issue of Colored Stone magazine,a publication whose editor strongly supported James, Dr. Joel Arem made the point that due to the melting temperature of the materials, tourmaline as well as topaz and garnet; "Lattice diffusion (as with andesine)
would not be possible, because the crystal structures would never
relax sufficiently to allow atomic mobility" Further, he summed up the proof in the images of diffusion offered by James: “In all these cases, the mechanism of coloration appears to be a simple variation of dyeing.”
In January of 2012, the World Gem Society issued the 2012 Jewelers Guide to Tucson Treated & Created Gems, later relabeled as simply the 2012 Jewelers Guide to Treated & Created Gems describing a wide variety of gems that were being treated. American gem dealer, Jeffery Bergman, wrote a review of this book, detailing some of the shortcomings.
Links
* International School of Gemology

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