The Latest on Synthetic Diamonds


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The largest blue HPHT synthetic diamonds to date: a 5.26 ct heart shape and a 5.27 ct emerald cut. Both were graded as Fancy Deep blue. Photo by Terry Poon.

Dr James Shigley, GIA distinguished research fellow, is one of the foremost experts in diamonds and their identification. In this presentation recorded at the 2017 JCK Las Vegas show, he shares the latest developments about HPHT and CVD synthetic diamonds, and information on GIA’s ability to identify them.

Gem-quality synthetic diamonds became commercially available in 1986. Since then, the production and quality have steadily increased. “Synthetic diamonds have a place in the market as long as they are properly disclosed at the time of sale,” Shigley said. The increased use of synthetic diamonds, also referred to as laboratory grown or man-made diamonds, in jewellery and their marketing to consumers make accurate identification and disclosure even more important, so that buyers can make informed decisions.  

Synthetic diamonds have a place in the market as long as they are properly disclosed at the time of sale.
Dr James Shigley, GIA distinguished research fellow

GIA’s research teams have years of experience of examining natural and synthetic diamonds. That research, coupled with advanced technology, enables GIA to positively identify man-made diamonds, separating them from natural gems. In addition to screening every diamond submitted for grading to confirm its origin as natural or lab-grown, the Institute offers a specialist service to screen parcels of melee (small diamonds that are approximately 0.005 to 0.25 ct and used in jewellery), offering clients an extensive analysis that differentiates natural diamonds from synthetic diamonds. Shigley also discusses the GIA iD100™, a new instrument that definitively separates natural diamonds from synthetic diamonds. 

The Latest on Synthetic Diamonds


Shigley received his undergraduate in geology from the University of California, Berkeley, and his doctorate in geology from Stanford University. He joined GIA in 1982 and helps direct GIA’s research activities in the identification of diamonds and coloured gemstones. He has represented the Institute’s work around the world, giving lectures and publishing his research.