In the U.S. there is a program called Frontline. In my opinion it is a program that can be taken seriously. It is broadcast on PBS stations. I don’t know if it is broadcast in other parts of the world.
Frontline did a special about man made diamonds. If memory serves, DeBeers discovered that if a certain frequency of light was shined on the artificial diamond it fluoresced for a few seconds after the light was turned off. Apparently this is something that real diamonds are incapable of.
FWIW
Jim