The “world’s largest lab-grown blue diamond” is a 10.07 ct. fancy deep blue SI Emerald cut. Its IGI grading report can be seen here.
Earlier in January 2016, GIA’s New York laboratory examined a 5.03 ct fancy-color HPHT-grown type IIb synthetic diamond produced also by our facilities. This emerald-cut lab grown diamond was color graded as Fancy Deep blue. This is a very attractive color with no other color component, a prized rarity among natural type IIb diamonds (the Blue Moon, for instance, was graded as Fancy Vivid blue). It had VS1 clarity, with only very small metallic inclusions and a cavity observed at the girdle.