Until 2009 the United States trade used the AGTA GTC for coloured stone identification reports covering clarity enhancement, fillers and country of origin.
The AGTA Gemological Testing Center is closed and issues no reports. AGTA's own about page states that the GTC closed in 2009 after operating for over a decade from New York, and no laboratory service appears anywhere on the current AGTA site. AGTA continues as a trade association based in Dallas, Texas; its timeline positions the launch of the GTC at 1998 but states no founding year in prose, so none is recorded.
Nous vérifions les négociants, pas les pierres. Un rapport de laboratoire décrit une pierre à une date donnée ; il ne constitue pas une garantie de valeur, et il ne nous appartient pas de le valider.