Fall 2009

New Technologies Face Off with New Realities

It’s no secret that gem treatments are becoming far more sophisticated and challenging to identify. Look no further than diamonds processed by high pressure and high temperature (HPHT), corundum diffused with beryllium, and topaz and other gems subjected to ultra-thin coatings. When some of these treatments were introduced, we did not know if the testing methods then available to gemologists and gemological labs could characterize them reliably. Fortunately, just as advances in technology have led to more sophisticated treatments, they have also hastened the development of powerful analytical techniques.  Many of these techniques are now common in fields such as chemistry, physics, and materials science, and enterprising researchers are learning to adapt them to problems of gem identification. 

We have seen this over the years in G&G with, for example, the harnessing of the Raman spectrometer, first to identify inclusions in gem materials (and the materials themselves) and later to record photoluminescence spectra that help characterize HPHT-treated diamonds. Virtually unknown in gemology a decade ago, laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) is now routinely used to identify Be-diffused ruby and sapphire. As featured in the Winter 2007 G&G, GIA and other gem laboratories are investigating the application of fluorescence spectroscopy to detect synthetic and treated colored diamonds. In the Summer 2008 issue, scientists at D. Swarovski & Co. showed us how X-ray photoemission spectroscopy can reveal characteristics of surface-coated vs. diffused topaz.  

This issue of G&G introduces gemological applications for two additional instruments that have been used successfully in other fields. In the lead article on “green amber,” Ahmadjan Abduriyim and coauthors identified a diagnostic signal with nuclear magnetic resonance (NMR) spectroscopy that proves whether a natural resin (amber or copal) was treated with a new two-stage heating process. Although NMR requires that a portion of the sample be destructively analyzed, the study offers valuable insights into how the treatment can artificially “age” copal so that it resembles amber (with a distinctive yellowish green color in some cases). In their article on the “fluorescence cage,” Inga Dobrinets and Alexander Zaitsev employ fluorescence microscopy—a technique widely used in the life sciences—to identify type I diamonds that have been subjected to HPHT treatment. This could provide a rapid screening technique for gem laboratories.

While the application of new analytical techniques to gemology is not always immediately apparent, an awareness of them is critical as new treatments and synthetics reach the marketplace. We urge every gemologist to stay alert to developments in other fields that might have potential in gemology. In the meantime, escalating technologies provide a fascinating arena for face-offs between new synthetics and treatments and the means of accurately and efficiently identifying them.

And while we’re on the subject of new technologies, in early October G&G introduced a monthly e-newsletter, the G&G eBrief. This publication reports breaking developments in gemology—new materials seen in the GIA Laboratory, the latest treatments, emerging localities, and other must-have-now information for the practicing gemologist. If we have your email address on file, you should have received it.  If you did not, please email us at gandg@gia.edu. Free to all in 2009, it will be delivered exclusively to the journal’s subscribers starting in January. Prices for the print version of G&G will be going up in 2010 to offset higher printing and mailing costs, but we believe that the value of the journal—and of the new G&G eBrief, as well as additional benefits soon to be announced—will make your subscription to G&G more indispensable than ever.

Brendan M. Laurs
Editor