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.
Compilado a partir de agta.org, disponível em 16 de agosto de 2026.
Verificamos os revendedores, não as pedras. Um relatório laboratorial descreve uma pedra numa determinada data; não constitui uma garantia de valor e não nos cabe a nós assumir a responsabilidade pelo mesmo.