Identifying Lab-Grown Diamonds
Gem quality synthetic diamonds are more available in today’s jewelry marketplace than ever before, causing both interest and concern among jewelers about the material’s nature and whether it can be identified by gemologists or gemological labs.
Gemological Institute of America has studied synthetic or "man-made" diamonds extensively over the past 30 years, and GIA knows a great deal about how they are produced and can be recognized. While synthetic diamonds are lab-grown or factory produced, their chemical and physical properties correspond very closely to those of natural diamonds.
Some people might refer to synthetic diamonds as imitations or simulants, but this is incorrect. Imitations like cubic zirconia or synthetic moissanite, which only look like diamond, have very different chemical and physical properties. This allows trained gemologists to recognize them readily. However, synthetic diamonds are much harder to detect.
In some cases a trained gemologist can recognize these synthetic and treated diamonds by using standard gem-testing equipment. In other instances, positive identification must involve testing the diamond using advanced scientific instruments at the GIA laboratory. At GIA, they have created a large database of information on the gemological properties of diamonds of all kinds, which can be used to help develop additional means of diamond identification.
Source: www.gia.edu