Buying guides2 guides

Gemstone certification, explained: what a laboratory report proves and what it never can

A dealer in Bangkok sends three photographs and a PDF, and the PDF is what you are really being asked to trust. Certified, in the coloured stone trade, means only that an independent house has looked at a stone and written down what it saw: the material, whether it grew underground or in a factory, what has been done to it since, and, where the extra fee was paid, which country the testers believe it came from.