High Quality Content by WIKIPEDIA articles! A superhard material is a material with a hardness value exceeding 40 GPa (gigapascals) when measured by the Vickers hardness test. They are highly incompressible solids with high electron density and high bond covalency. As a result of their unique properties, these materials are of great interest in many industrial areas including, but not limited to, abrasives, polishing and cutting tools and wear-resistant and protective coatings.