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AnchorCert Sees Flood of Glass-Filled Rubies

Jul 6, 2010 10:41 AM   By Jeff Miller
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RAPAPORT... AnchorCert gemologists at the Birmingham Assay Office in the U.K. have observed a large number glass-filled rubies being submitted in recent weeks. Many of the rubies in question were bought in the good faith that they were both natural and untreated.
Senior gemologist Anu Manchanda noted that "This type of treatment has been around for a few years now, but we seem to have suddenly seen an unusually high number."

In their natural form, these rubies are comprised of poor-quality, dirty corundum and subjected to bleaching to remove dark patches of color. The bleaching also affects their structure, making them brittle and unstable, according to the related AnchorCert release, so molten-colored glass is then used to fill the cracks. The resulting rough gem can be cut and polished, but will always have a characteristic lack of clarity, rather like a boiled sweet, Manchanda explained.
A trained jeweler can easily detect these treatments using tenfold magnification that will reveal bubbles, blue flashes of light and evident fractures running up to the surface under reflected light.

For additional information, contact AnchorCert via its website:

In related news, the American Gemological Laboratories (AGL) discovered a new ruby treatment recently:


Tags: Jeff Miller, Laboratories
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