ratio of.72 to trhe sellers side, page-50

Lets not muck around here. The hardest known metal alloy, and the hardest known metal in general, is a type of carbon steel, Alloy 1090. With a tensile strength of .84 GPa (122,000 psi) and a yield strength of .64 GPa (67,000 psi), carbon steel is surpassed in hardness only by very hard nonmetals, such as ruby, diamond, or aggregated diamond nanorods.
I like the sound of "nanorods" myself.
Or ad a bit of weight to get a swing going... Depleted uranium, the metal of choice for tank shells, is not harder than tungsten carbide or carbon steel but it is more dense, which is preferable for projectiles. Hang in there chaps!! Cheers