Before I go into a long tirade about this, let’s first examine the last major Thailand scam…
The last time the gem world was rocked by dishonest Thai dealers using atrocious practices targeted corundum, specifically sapphires which were subjected to beryllium diffusion. Beryllium diffused sapphires were released like the Great Flood upon the market into the hands of unsuspecting dealers. The problem was so great that it threatened to cripple the market for sapphires. Beryllium treatment is a process that replaces the trivalent aluminum in the crystal lattice with divalent beryllium. The color change process is very complicated, and due to this, other trace elements often give away a signature that can be detected. Without going into extreme detail (which would take pages to discuss), a brief example of Be treatment could be when: [Mg2+ + Be2+] > [Ti4+ + Si4+] a trapped hole of color is formed by Be2+ and Mg2+ to produce yellow color. If though instead you reverse this process so that [Ti4+ + Si4+] > [Mg2+ + Be2+], more donating electron ions exist to deform the trapped color hole and yellow color is not produced. Blue color can be produced in sapphires using the transfer of Fe2+/Ti4+. This practice lasted for years, even though gemologists could detect the process, many dealers passed the stones along unknowingly representing them as legitimate heat treated only or worse yet, natural untreated gems. For the most part this problem has settled down, but still rampantly plagues online auction venues such as eBay.
Now, in regards to Thailand and topaz… The industry has been aware of inexpensive colorless or light tan topaz being treated with Cobalt-60 radiation or X-Ray radiation that turns the stones into a lovely deep reddish/orange to deep pinkish-brown color. The purpose of this would be of course, none other than to defraud a buyer by making the material appear to be very costly precious or imperial topaz. The problem is, that with only 1 day’s worth of exposure to natural sunlight, the process is completely destabilized, and the material’s color washes out to it’s original color (or lack thereof rather).
The difference in price between common colorless/tan topaz and true imperial topaz is a difference between as little as $1-5/ct for common material and upwards of $1,000/ct for stones 10cts+ in size of super rich color imperial topaz. This practice has had an immense impact on the trade and is the equivalent of taking a direct hit by a 20 megaton hydrogen bomb. It is a seriously destabilizing move against the industry by fraudulent individuals.
This case has become rather personal for me, in that someone I am close to has been affected by this scam. The individual purchased a 30 ct+ topaz from a dealer that operates off of eBay. The material was represented as untreated and was sold for about $1000 for the stone. This unfortunately should have been the individual’s first clue, when the material was priced around $30-35/ct, that this could not possibly be the famed material from Oro Preto, Brazil that commands prices of $500-1000/ct in sizable stones. But regardless, this person was misled – as the material was represented by the dealer as untreated. Upon seeing this material, I immediately knew that something was dead wrong. The saturation was too deep, there were a couple bands of internal color zoning that are atypical of zoning formations of precious topaz, and it flat out just didn’t look right. Upon suspecting the worst, I gave my opinion on the material, and suggested that we subject it to natural sunlight. I took pictures prior to subjecting the stone to natural light. Unfortunately, I didn’t have any AA batteries available for my digital camera, so I used a film camera (hope the shots came out ok). When I develop the pictures I will upload them here.
The process was timed to expose the material for 8 hrs to direct sunlight. What happened within the first hour of exposure alone was horrifying… the material lost half of it’s color saturation. Within subsequent hours, the material lost more and more color saturation. What started out as a very deep gorgeous reddish brown topaz was reduced to barely a light tan stone within 5 hours. eBay is still a huge source, if not the number one source of this treated material. I can’t stress enough how important it is to know your source and know what you are buying and what treatments are out there.
