The Evolution of Laboratory-Grown Diamond Evaluation at GIA | GIA Knowledge Sessions Webinar Series

GIA Knowledge Sessions Webinar - recorded live on October 1, 2020.
Both the quality and quantity of laboratory-grown diamonds have increased in the past several years. GIA’s reports for laboratory-grown diamonds have evolved as consumers’ knowledge and interest have grown. What has changed in the 14 years since GIA first started issuing reports for laboratory-grown diamonds? Discover the evolution of these man-made gems and learn about GIA’s new reports for laboratory-grown diamonds with Senior Research Scientist Mike Breeding.
Read more of Dr. Mike Breeding's research:
www.gia.edu/gems-gemology/spr...
www.gia.edu/gems-gemology/sum...
Questions answered by Dr. Ulrika D'Haenens-Johansson during the live webinar:
Q. Are CZs the same as lab-grown diamonds? If the chemical makeup is the same, will they ‘test’ the same using the technological tools used?
A. CZ (cubic zirconia) is zirconium oxide (ZrO2), a chemically distinct material. It looks like diamond, but is fundamentally different, and is known as a simulant. Laboratory-grown diamonds share the same chemical structure as natural diamonds - tetrahedrally bonded carbon atoms. They differ in their origin. Simulants will not test the same as either natural or laboratory-grown diamonds, as long as appropriate screening instruments are used.
Natural and laboratory-grown diamonds can also be identified with appropriate instrumentation as well. This is done for all diamonds submitted to GIA.
Q. Is CVD the same hardness as natural diamonds? Can it be scratch with a diamond testing pen? thank you
A. Yes, as they have the same chemical structure, they share many properties, including hardness.
Q. Do the quality of the cut varies on lab-created diamonds like the natural? Or is the rough more consistent to lend itself to a well-cut stone?
A. As with natural diamonds, the full range of cuts are possible with laboratory-grown diamonds. Initially, CVD laboratory-grown diamonds were mainly cut to shallow cuts, and were often rectangular or square cuts. Now, however, depth is not an issue, and good quality round brilliant cuts and others are available.
Q. Are most lab-grown diamonds identified by an engraving on the girdle? If not, how can we determine instore?
A. All laboratory-grown diamonds will be inscribed with "LABORATORY-GROWN"

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