It is a joint decision of the profession and the French Union of Jewellery not to grade synthetic diamonds, unlike other international laboratories. These stones do not have to be evaluated on the same scale as natural ones, because they are an imitation of the diamond and must remain so. This decision is unanimous in the profession except for those who want to promote this [lab-grown] material. But it must be remembered that the increase of synthetic diamonds on the market will bring down their price. Natural diamonds will always be desired for what they are, a rare and precious natural resource. If [synthetics] are graded, this must also be done for other synthetic stones. Not grading these stones helps to differentiate and isolate them.
- Aurélien Delaunay, Director, French Gemmological Laboratory, in Rapaport Magazine