https://www.youtube.com/watch?v=hW2XtG7hxF0
(They make great fake diamonds these days. I wouldn’t let my husband buy a real one.)
An enjoyable read about synthetic diamonds.
From the early days.
IIRC there is a follow up on this article.
Yes, DeBeers has since jumped in with both feet.
The New Diamond Age
https://www.wired.com/2003/09/diamond/