There was a story in Wired mag about mainstreaming industrial diamonds. The Russians had a machine that worked half of the time, that is, pretty well but was not consistent for production. The engineer bought the rights for it and improved it with modern electronic pressure controls and then showed Debeer. They about had a heart attack.
That system of making synthetic diamonds is now owned by retired US General Carter Clarke, who founded a company called Gemesis. He has perfected the technique and is producing gem quality stones in Florida.
The diamond Gemesis creates are, according to them,
"Very high-quality. The cut, color and clarity of both our colorless and fancy yellow color diamonds are consistent with the top-tier of mined diamonds. And, in fact, all Gemesis lab-created colorless diamonds are Type IIa, which is the purest form produced in nature and accounts for only 2% of the global production of mined diamonds"
They can make colorless diamonds up to ~1.6 carats, and fancy yellow up to ~3 carats. Pink to ~1.25 carats. Pricing is about 50%-75% that of equivalent earth mined.