GIA Identifies Mixed Natural-Synthetic Diamond

The Gemological Institute of America had identified a stone that is a composite of synthetically grown and natural diamond.

It was described as a 0.64-carat fancy grayish greenish blue cushion modified brilliant. It turned out to have a “CVD synthetic diamond overgrowth,” according to GIA, which described the finding in the Spring 2019 issue of Gems & Gemology, its quarterly scientific journal.

The grayish greenish blue was caused by the gray and blue components from the CVD layer and the yellow from the substrate.

“The resulting color was likely the main motivation for growing the CVD layer on top of the natural diamond, though the extra weight gained could also be a factor,” according to the article.

GIA added: “With the second of these composites seen at GIA, this could be a new type of product entering the market.

“Earth-grown diamonds with synthetic diamond grown on the surface require extra scrutiny due to the presence of natural-looking features, both spectroscopic and gemological. Careful inspection still reveals the presence of synthetic indicators, which expose the true nature of the diamond.”