Grading Man-Made Diamonds
Man-made gem diamonds have been extensively studied by gemological researchers for the past 30 years, and much is known today about how they are grown and how they can be identified.
Synthetic diamond identification means distinguishing a natural diamond that formed over a long time, and very long ago, from a synthetic diamond that formed very quickly and very recently.
GIA has screened every diamond submitted to its laboratory for grading for more than a decade to determine if it is natural or potentially man-made or treated. Following the initial screening, any diamond that is potentially man-made or treated undergoes rigorous examination to confirm if it is natural or man-made, and what treatments, if any, have been applied.
GIA can definitively identify both HPHT and CVD-created man-made diamonds.
What Will A GIA Grading Report Tell Me?
GIA began to offer a report service for synthetic diamonds in 2006. These Synthetic Diamond Grading Reports, which GIA continues to offer, are distinct from GIA grading reports for natural diamonds in both their appearance and the information provided. They clearly identify that the diamond is man-made or laboratory-grown, and they evaluate color and clarity using descriptive ranges rather than the specific grades of the color and clarity scales.
When these reports were introduced, there was a range of opinion in the trade about GIA grading synthetic diamonds. Since synthetic diamonds continue to be rare, and to differentiate them from what is reported on grading reports for natural diamonds, only color and clarity ranges are used.
In addition, the man-made diamond's girdle is laser inscribed with its report number and a statement that the stone is laboratory- grown. GIA does this for every man-made diamond identified in its labs.
The inscription on the girdle can be key to its identification.
The reports also use the other Federal Trade Commission (FTC) approved terms, man-made and lab-grown, for synthetic diamonds. There are legal and ethical requirements that a jeweller must disclose a gem's identity at the time of sale. This helps ensure consumer confidence in what they are purchasing.