Inside the Sandia Lab's Z Machine, even diamonds aren't forever:
Sandia’s Z machine, by creating pressures more than 10 million times that of the atmosphere at sea level, has turned a diamond sheet into a pool of liquid. ...
in the experiments, the applied pressure came from shock waves passing through the diamond. The waves were created by impacting the diamond with tiny plates hurled using Z’s huge magnetic fields at about 20 times the speed of a rifle bullet.
Link - via starspirit