A new corundum treatment has recently emerged that, in a very short time, has created a storm of controversy. In December 2001, these authors were told of a new type of heat treatment being done in Thailand that could take the abundant light pink sapphire from Madagascar and change it to a beautiful “padparadscha” color. The only other information available from the treaters at the time was that the stones were being heated in an oxygen atmosphere and they believed the process was new and revolutionary.
 
We were subsequently told that in addition to the pink Madagascar material, green sapphire from Songea, Tanzania, and even old stocks of Thai ruby were involved. When, in early January, we had our first opportunity to examine some of these stones, it was clear that more than one type of corundum was being treated by this process. By that time, gemologists had noted that many of these stones were different from the heat-treated stones we typically examine, which gave rise to the belief that there was more to the “heat” treatment than was being disclosed. Click here for the full preliminary report of GIA’s examination of 48 stones treated by this purportedly new process.
Jan. 31, 2002