orange sapphire e updates
Palagems.com e-mail alerts on treated orange sapphires
Note: Since late in 2001, treated sapphires from Thailand have created a great deal of controversy (see ‘The Skin Game‘ and ‘Understanding the New Treated Pink-Orange Sapphires‘ for full details).
To set the historical record straight, below we reproduce the earliest of our e-mail alerts on this important topic.
Songea Orange Sapphire
Issued November 16, 2001
***** NEW HEAT PROCESS FOR
SONGEA SAPPHIRE *****
Sources from Thailand are reporting development of a new heating process for dark orange-red sapphire from Tanzania's Songea district. The process has apparently been developed by a burner in the Thai gem trading town of Chanthaburi, and the material has been selling in that market since early September, 2001.
The process apparently involves heating material that previously did not respond well to treatment. Resulting colors run the gamut from a bright red reminiscent of Burma red spinel, through orange reds, to a pure orange. Golds and yellows are also reported.
News Flash: Treat
Orange Sapphires Raise Concern
Issued January 9, 2002
***** ORANGE SAPPHIRE UPDATE
Several months ago we reported on a new treatment process in Thailand for Songea (Tanzania) orange sapphires. We have now had a chance to examine a number of these stones from both Songea and Madagascar and they appear to be treated by a process involving heat and/or surface diffusion/irradiation.
The color range of these goods runs the gamut from yellow through golden yellow, to orange (including the range that encompasses padparadscha) and even into borderline ruby colors. Inclusions within the stones indicate that they have been exposed to high-temperature heat treatment (see attached photo of melted crystal inclusion). But this is no ordinary heat treatment.
An unusual characteristic is the stones' surface-based color (see attached photo). You can clearly see that stones feature a pink core with a yellow-orange skin. But unlike normal surface-diffusion treated gems, the facet junctions do not show any highlighting. Instead, what is seen is a layer of yellow-orange that follows the shape of the cut stone (evidence that at least the final portion of the treatment is applied to the cut stone, rather than the rough) exactly. The AGTA lab in New York is currently studying these stones, and their initial report can be found here.
We have also provided a number of specimens to the GIA for analysis. Keep in mind that the jury is still out on these stones regarding the exact method of treatment and their color stability. As more information arrives, we will provide updates. For the moment, we advise caution in their purchase.
Update on orange
Issued January 11, 2002
***** ORANGE SAPPHIRE UPDATE
First, we want to thank all of you who have written regarding our Orange Sapphire News Flash a couple days ago. The response was tremendous, with many readers shedding additional light on this fast-evolving situation. With the new information, we have updated our report on these treated yellow, orange and orange-red sapphires. You can see the revised version here.
This report also includes information on the proper method for performing a fade test. Please take the time to read it.
Breaking news on
Issued January 16, 2002
We have updated our report on the new treated orange sapphires, with important news on these stones. This newly updated version contains information on diffusion in corundum that goes a long way towards explaining what might be occurring in these new stones. See it here.
Issued January 18, 2002
If you read our last update on the new orange sapphire treatment, you will have seen that John Emmett of Crystal Chemistry has provided us with important information on this treatment. Mr. Emmett has now had a chance to review our report and has corrected a few errors and provided further suggestions. We have now incorporated these into our report.
Please note that this revised report replaces all previous editions. Ignore the previous versions. ;-) Again, we thank Mr. Emmett for his important contribution, as well as our many other correspondents who have contacted us with information.
Issued January 29, 2002
***** GIA ON ORANGE SAPPHIRES
The GIA has today issued a preliminary report on their study of the new treated orange sapphires. You can access their report at:
Orange sapphire update
Issued February 19, 2002
****** TREATED ORANGE SAPPHIRE
In an action-packed meeting between laboratories and dealers from around the world, the new treated orange sapphires were discussed in detail before the recent Tucson show. Richard Hughes was in attendance and has written a full report for The Guide, which will appear in the March-April issue. Because of the importance of this issue, Palagems.com and The Guide are making this report available online immediately.
Treated orange sapphire
Issued May 13, 2002
****** TREATED ORANGE SAPPHIRE UPDATE ******
On May 4-5 2002, the GIA hosted a meeting to discuss the treated orange sapphires from Thailand. At this meeting, Dr. John Emmett presented results from his experiments on these stones. In summary, Dr. Emmett has closely reproduced this treatment in his lab.
Dr. Emmett and Troy Douthit have written a report of the methodology of these experiments and have graciously allowed us to reproduce it at Palagems.com. This report is of tremendous importance and we believe it is the first signal of a complete re-examination of treated gemstones. See it here.