Photo of a synthetic diamond factory showing a number of HPHT (high pressure, high temperature) cubic presses.
https://s3-us-west-1.amazonaws.com/h...nd_factory.jpg
2:36 video of how synthetic diamonds are made:
https://www.youtube.com/watch?v=NkMkcetAiV4
Previously:
https://www.homemadetools.net/forum/...960#post125012
https://www.homemadetools.net/forum/...2930#post97555