The 6.87-carat near-colorless CVD diamond was shaped to resemble a natural rough octahedral crystal but showed distinct synthetic features under microscopic and spectroscopic analysis.GIA’s tests confirmed the stone’s synthetic origin, noting polishing marks, facet junction roughness, and luminescence patterns inconsistent with natural diamonds.

No evidence currently suggests widespread substitution of synthetics for rough natural diamonds, but existing detection tools could be adapted if such cases increase.

The near-colorless stone is believed to be the first time creators of a synthetic chemical vapor deposition (CVD) diamond have shaped it to resemble a rough diamond, according to an article in the spring issue of the institute’s Gems & Gemology quarterly journal.

Upon investigation with the use of raman spectroscopy, the results confirmed that the material was a diamond, with its near-octahedral shape similar to that of a natural rough crystal. Further analysis showed that it was not a true octahedron, as only one set of opposing faces was parallel. Microscopic observation under differential interference contrast revealed extremely flat faces marked mainly by parallel polishing lines, unlike the growth steps and trigons typically seen on natural octahedral faces. The facet junctions were extremely rough, possibly due to measures taken to improve the color, after which the main faces appear to have been repolished, the institute explained.