AGTA Gemological Testing Center
Until 2009 the United States trade used the AGTA GTC for coloured stone identification reports covering clarity enhancement, fillers and country of origin.
The record
What it covers
Worth knowing
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.
Compiled from agta.org, read on August 16, 2026.
We verify dealers, not stones. A laboratory report describes one stone on one date; it is not a guarantee of value, and it is not ours to stand behind.