According to this article in PhysicsWeb, Diamonds are not forever (August 2005), diamond is no longer the hardest material. Don’t you just hate it when the underpinnings of the world, the things you know, turn out to be untrue?!
The hardness of a material is measured by its isothermal bulk modulus. Aggregated diamond nanorods have a modulus of 491 gigapascals (GPa), compared with 442 GPa for conventional diamond.
