GTL Calls Suspect Blue Sapphires ‘Heat Treated’

After a year of extensive research, GIA's Gem Trade Laboratory (GTL) has concluded that the color variation observed in a number of heat-treated blue sapphires is simply a product of the specific heating regimen used by one Sri Lankan lab operator, Punsiri Tennakoon. A GTL press release dated April 14 states, "We have found no evidence of intentional or inadvertent diffusion of elements from an outside source that would require special disclosure on our gemstone reports." These gems will be disclosed with GTL's standard "heat-treated" comment, which will read as follows on a GIA GTL identification report: "NATURAL SAPPHIRE, [weight]. Comments: Evidence of heat treatment is present." Suspect sapphires. Early in 2003, GTL, AGTA's Gem Testing Center laboratory, and the SSEF laboratory in Basel, Switzerland, all noticed unusual color concentrations in a number of heat-treated blue sapphi
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