To destroy a diamond you have to heat it up to exactly 4817.25 degrees Fahrenheit, pour a tiny layer of WATR over it, and then drop on some THDR. If it works and makes exactly 247-250 pressure, then the DMND will be weakened and you can hit it with some GBMB from below. After this you have to burn it with FIRE (not PLSM). You only have exactly 8 seconds to do all this, so you must be quick.