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The CIBJO Colored Stone Commission in session at the 2012 CIBJO Congress in Vicenza, Italy.



  CIBJO commission declines to alter description of lead-glass filled rubies


June 11, 2012


Meeting at the 2012 CIBJO Congress in Vicenza, Italy, the organization's Colored Stone Commission was called n to consider the hot-button topic of lead-glass filled rubies. Many of these treated gemstones stones have large and frequently unquantifiable amounts of lead glass in them, and are popularly called "composite ruby" by members of the colored stone community.

But CIBJO Coloured Stone Commission President Nilam Alawdeen reported that, after a long discussion, the committee had recommended that the word "composite" not be considered the correct term to describe such gemstones.

Consequently, it was decided to keep the nomenclature for this treatment as it is presently described in the CIBJO Gemstone Book, which is "lead glass filled open fractures and cavities." The seller is recommended to indicate that the gemstone requires special care.

During the commission meeting, Alawdeen said that, in his home country of Japan, labs have not been able to determine the amount of glass in such rubies, specifically because it would have require the destruction of the stones submitted for testing.

During the meeting, Menahem Sevdermish, of EGC, Israel, and the founder of Gemewizard®, pointed out that samples he had received in his lab disintegrated into almost colorless, sponge-like pieces of corundum that were fused together by lead glass. "I would not even want to call it ruby," he stated.

GIAA Thailand's Ken Scarratt, who is president of the CIBJO Pearl Commission and vice president of the Gemological Commission said that the phenomenon of glass filling was not restricted to corundum, but also occurred in beryl, in particular emerald. "We know that 95 percent of ruby in the market is treated, lots of it with glass filling. It is ultimately all a matter of how stable it is," he stated.

Later, during the meeting Gemological Commission, Elena Gambini of Italy provided the meeting with an overview of the current position of the Laboratory Manual Harmonization Committee (LMHC) on the nomenclature for glass filled ruby. She demonstrated the various options and ways to describe the stones and presented an added category: "Ruby or corundum with/and glass/manufactured product."

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