A 16.41-carat laboratory-grown diamond believed to be the largest ever created using the chemical vapor deposition (CVD) method has been looked at by the Gemological Institute of America (GIA).

The lab says the princess-cut stone, which was grown by Shanghai Zhengshi Technology Co., has the “observable characteristics” of a diamond produced using CVD methods. It was examined by GIA’s vice-president of research and development, Wuyi Wang, PhD.

“The first CVD diamond I examined in 2003 was a 0.23-carat pear shape with clear brown colour,” Dr. Wang says. “This 16.41-carat laboratory-grown diamond demonstrates the advances in CVD growth technology. This achievement has important implications for the many scientific and industrial applications for high-quality laboratory-grown diamonds.”

The diamond is G colour and VVS2 clarity, GIA says. Detailed spectroscopic readings confirmed it was not treated post-growth to improve its colour.

“GIA has examined thousands of laboratory-grown diamonds since the first gemmological description of them by Robert Crowningshield in 1971,” says the group’s executive vice-president and chief laboratory and research officer, Tom Moses. “In the decades since, we have shared the results of our detailed research; this is an important aspect of our consumer protection mission.”

A brief report by Wang and research associates, Stephanie Persaud and Elina Myagkaya, is available on GIA’s website. It will also be published in the lab’s quarterly journal, Gems & Gemology.