LMHC Labs Agree on Glass-Filled Ruby

Prior to treatment, much of the low-quality, highly fractured ruby that comes from Madagascar is unusable. However, masking these fractures by introducing a glass filler during treatment with low heat results in a relatively transparent commercial gem product, which raises the question of value. Meanwhile, the seven member laboratories of the Laboratory Manual Harmonization Committee are addressing the issue of how best to describe the filler. LMHC members are the American Gem Trade Association Gemological Testing Center (United States), CISGEM (Milan, Italy), GAAJ (Japan), GIA (United States), GIT (Thailand), Gübelin Gem Lab (Switzerland), and SSEF (Switzerland). Many of the LMHC labs have agreed on standardized nomenclature to describe glass-filled fissures and cavities when there are indications that the clarity of the corundum has been enhanced or modified by the low-heat introd

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