I believe the 'known' maximum size for CVD (synthetic) diamonds is approx 1.5ct, for a round brilliant cut, costing ~$7k. Those that own the technology are caut

I believe the 'known' maximum size for CVD (synthetic) diamonds is approx 1.5ct, for a round brilliant cut, costing ~$7k. Those that own the technology are cautiously entering the gem-grade market and have been selling premium stones to fund their venture. You really can't tell the difference, even with a refractometer. Gem cutting predominantly exists within the traditional diamond trading centers and is an intensive educational process. If a large quantity of 'perfect' rough diamonds hit the market, they will know. Fwiw, I own a jewelry store and most recently I acquired what I believe is a CVD diamond.. It's stunningly flawless with a very slight color and a slightly shallow cut. It weighs in at 2.8ct, which is very puzzling. I sent it to GIA for certification.