Over the last several months, there has been extensive discussion and research related to the new color-altered sapphires that have been treated mainly in Thailand. The cause of color in these stones has been a major focus of the investigation into this new treatment, as has identification of the treatment in all stones to which it has been applied.

Following detailed analyses, replication experiments, validation by independent researchers, and extensive discussions, it has been unequivocally established that the color change is caused by the diffusion of beryllium from an external source into the corundum.  Beryllium diffused into corundum, in an oxidizing atmosphere, at high temperatures, is the single causative agent of color change in this new process. Beryllium diffusion is very similar to the diffusion of titanium into corundum that creates a blue color layer, and thus both will be described similarly in our reports. The primary effect of the beryllium diffusion is an added yellow color component, although other effects have also been observed. Depending on the starting material, the colors produced by this technique now present on the market are yellow, orange, orangy pink, orange-red, green, green-blue and violet.

The majority of these treated stones can be identified through a combination of standard gemological testing techniques. We are now focusing our research efforts on the establishment of robust identification criteria for those stones that are not identifiable by established testing methods.  We believe that these criteria will involve both traditional gemological testing and advanced analytical techniques; the latter will undoubtedly include instruments that are routinely used today in well-equipped gemological labs, but we are also looking at methods that historically have not been accessible to gem testing laboratories.

Establishment of these criteria is being given the highest priority at both the GIA Gem Trade Laboratory and the AGTA Gemological Testing Center, and we will be using all of the resources at our disposal, including consultation with outside experts.  We believe these efforts will help allay the concerns of dealers and jewelers alike regarding this new treatment procedure, and will allow consumers to purchase corundum with certainty and confidence.