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.
The object of the experiment at the National Nuclear Security Administration facility was to better understand the characteristics of diamond under the extreme pressure it would face when used as a capsule for a BB-sized pellet intended to fuel a nuclear fusion reaction.
Why use diamond at all? It was hoped that diamond would help smooth out the applied pressure loads and keep the capsule implosion symmetric.
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.