Gemstones & Pearls/Gemology
Beryllium Diffusion & Disclosure
ICA Congress delegates focus on the new corundum treatment
Diffusion. Bulk diffusion. Beryllium diffusion. These words have swirled through the industry for the past year, leaving some jewelers confused and consumers wary of the multinamed treatment that turns some corundum into the highly valued pink-orange padparascha sapphire. Disclosure of this treatment was one focus of the International Colored Gemstone Association Congress, held Jan. 6-10 in Jaipur, India.
The treatment, performed in Thai gem markets, is significant because beryllium can affect up to 90% of all sapphires in some way, says Shane McClure, director of identification services at the Gemological Institute of Americas Gem Trade Laboratory. Before GIA conducted tests, experts believed only sapphires from certain sources were affected.
Its also important because natural padparascha sapphires are much more rare and expensive than ones that owe their color to beryllium diffusion.
The beryllium treatment has negatively affected the market, said Douglas Hucker, executive director of the American Gem Trade Association, during a panel discussion on the topic. There was a missed opportunity at Tucson last year and a lot of money was lost, he said about sales of undisclosed treated sapphires at prices far above what they were worth. Soon after the treatment was identified, purchases of sapphires from Thailand particularly yellow, orange and orange-pink ground to a halt. If these stones had been properly disclosed, he said, they would have found a proper market niche and price structure.
How its Done
Beryllium diffusion occurs when sapphires are heated to 1,800&Mac251;C and above in conjunction with the element beryllium. Traces of the element diffuse into the stone, causing a permanent color change along surface layers and, in some cases, penetrating more deeply. (Older forms of diffusion in blue sapphires using iron and titanium as coloring elements penetrated only thin surface layers that could easily be polished off.) The new form turns natural green, off-pink and other colors into pink-orange, orange, red-orange and bright yellow. GIA says other colors are affected also, including blue, though this appears not to be a big concern at this time.
Japan has been greatly affected, said Akira Ito, an ICA director, because padparascha sapphires are coveted there. Since 2001, Japanese labs issued some 20,000 reports incorrectly describing the stones as padparascha sapphires, though its unlikely there were ever that many natural padparaschas certified in a lifetime. Because suppliers generally dont accept goods for return, its a big problem, he said.
Panelists also said the word diffusion has hardly any impact on consumers once they understand the process. A matter of some debate was the term bulk diffusion, which scientists said accurately describes this form of diffusion, though some in the trade say bulk gives consumers the wrong idea. At the congress, GIA reports referred to the stones as beryllium diffused.
Dr. Claudio Milisenda of the German Foundation of Gemstone Researchblamed much of the problem to nomenclature. In the ICA disclosure system, T stands for treated and is used for natural stones treated by a process that requires specific additional disclosure. E stands for enhanced and is used for natural stones enhanced by trade-accepted practices specific to each gem. If beryllium-diffused sapphires are classified as a T in the ICA system, why should fracture-filled rubies be classified as an E? Milisenda asked. These two cannot be viewed so completely differently as to warrant different disclosure codes.
by Robert Weldon
||At the Tucson gem fairs in 2002, Pala International, Fallbrook, CA, showed customers this sample of beryllium diffusion-treated Madagascar sapphires. The company didnt sell the stones. Photo by Robert Weldon.