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GIA identifies rare glass-filled lab grown ruby



The Gemological Institute of America (GIA) reports a 3.53-carat lead glass-filled lab grown ruby in the Spring 2021 edition of Gems and Gemology.  


The glass-filling technique is often applied to enhance natural ruby for clarity enhancement. This lab grown stone is discovered at its Carlsbad gem lab. “Examination of the stone under magnification showed a network of interconnected fractures. A pronounced blue and orange flash effect was observed throughout, proving the fractures were filled with lead glass,” the institute shared the details.


A staff gemologist at the Carlsbad lab Forozan Zandi suggested: “While it is unclear why anyone would go to the trouble to treat a synthetic ruby with lead-glass filling, gemologists should be aware that such material does exist in the trade.”


The last identification of glass-filled synthetic ruby traced back to 2012. It was the first example of such kind.

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