(IDEX Online) - GIA has graded its biggest ever lab grown polished diamond, a 34.59-carat emerald-cut stone (G color, VS2 clarity).The diamond, produced by Ethereal Green Diamond, in India, is more than twice the size of the previous record holder, a 16.41-carat princess-cut diamond from Shanghai Zhengshi Technology, in China, in January 2022.The 34.59-carat stone, measuring 24.94mm ??- 13.95mm ??- 9.39mm was tested at GIA's Hong Kong lab.GIA (Gemological Institute of America) says there have been significant advances in CVD (chemical vapor deposition) technology."This more than two-fold increase in size within one year is an impressive technical achievement in CVD diamond growth," said Tom Moses, GIA executive vice president and chief laboratory and research officer. "With such production improvements, correct identification and disclosure are critical to maintaining consumer trust."Researchers found small black graphite inclusions, some along the inside of the body, while others formed clusters of clouds between growth layers, according to a research note in GIA's Gems & Gemology.Microscopic observation showed a weak "oily" or wavy graining looking through the table, a feature sometimes seen in CVD laboratory-grown diamonds.Pic courtesy by Johnny (Chak Wan) Leung (GIA).