Warugaki missed a zero. Think 50,000 - 70,000 atm is the usual quoted figure for 'natural' processes and the HPHT (High Pressure High Temperature) process. Some of them go up to something like 130,000 atm.
You can make diamonds at much lower pressures using the CVD (Chemical Vapor Deposition) technique, but that's more like blowing particles into a "seed diamond crystal" instead of 'brute-force' crushing them.
Edit: Hmm, looked around. It is in theory possible to synthesize diamond using compression methods while in the metastable region (of the phase diagram). There's a... 'published' compression process that 'only' requires pressures of mostly around 5,000 atm, but it involves compressing the diamond out of a molten iron-carbon solution, and also requires a few cycles to 15,000 atm. The process is described in a 1931 patent by Hans Karabacek. But... I don't think anyone has replicate it yet. At least not feasibly.
Science isn't about refining diamonds by feats of strength...
brrrrrrrrrrrrrrrIntermolecular forceI didn't mean the chemistry behind it!!CoalCompressed at 6000 atmospheric pressureHold on! So the strength of your grip is six thousand atmospheres?!Covalent bond... Which I generated by vibrating my hand to achieve ultrasonic heat.ThermosonicDiamondTruth is, I'm quite science-savvy!You also need to apply heat of around 1600℃...Heh heh heh! Surprised?Oh no. That alone wouldn't be enough.Don't just add more that I don't understand!! One thing at a time!!Carbon molecule
