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| September/October 2003 |
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New Treatment Found in Blue Sapphire Researchers at the American Gem Trade Association Gemological Testing Center (AGTA GTC) issued a lab alert today on a new treatment discovered in blue sapphires. The process by which the gems are treated is currently unknown, but the effect is similar to diffusion: The process produces a light blue or colorless surface layer in an otherwise dark blue stone, effectively lightening its color and making it more marketable. At a panel discussion on beryllium diffusion in sapphire at the 2003 Tucson gem shows, researchers reported that beryllium diffusion had been used to produce this effect in very dark sapphire. The AGTA alert said that no trace of beryllium had been found in any of the sapphires they tested, but they did not rule out diffusion with a different element. The treatment can be detected by immersing the gem in methylene iodide and illuminating it with a diffuse light source. In those conditions, the light rim around the edge of the sapphire is clearly visible. The alert said that most of the treated gemstones the AGTA GTC examined were between two and 17 carats in weight and originated in Sri Lanka. Research is ongoing; the AGTA urged anyone with information about the new treatment to contact them at (800) 972-1162. Posted: October 14, 2003 |
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