[letstryagain]

You can tell which rocks are natural because of the flaws contained in them. The flaws in natural rocks can not be created using a synthetic process. Synthetic stones are flawless. Yes you can introduce flaws in synthetic stones but they don't look like natural flaws.

[Joeri]

How would you know? For all we know they figured that out years ago and are putting up a show of how impossible it is to reproduce natural flaws while laughing all the way to the bank. Anyway, even if you can't synthesize a perfect replica now, it will be possible someday.

This is a wider problem for all scarcity driven industries. As we improve materials science natural scarcity will go away, and those industries will either run towards intellectual property rights or be forced to change their business model.

[apricot]

The gemstone industry's approach to this is to call mined gemstones "real gemstones" or "natural gemstones" and ones made in a lab "synthetic gemstones". This leads the general public to believe that lab-created stones are somehow artificial or fake, like leather-imitation vinyl.

[snowwrestler]

Synthetic diamond research is not owned or controlled by the cartels that control the from-the-ground gem market. The processes and limits of making diamonds are the subject of scientific papers, industrial processes, academic conferences, etc.