Researchers from the National University of Singapore (NUS) have managed to create water that is corrosive enough to etch diamonds. This was discovered by mistake - the researchers attached a layer of graphene on diamond, and then heated it to a high temperature (to encourage bonding). Water molecules that were trapped between the diamond and graphene could not escape (because graphene is impermeable ).
The "trapped", heated water transformed into a supercritical phase that behaves differently compared to "normal" water. It even corroded the diamond.
This interesting discovery can have several applications - such supercritical water can be used for degradation of organic waste and also as a laser-assisted etching of semiconductor films.