Tungsten carbide is approximately two times stiffer than steel, with a Young's modulus of approximately 550 GPa,[6] and is much denser than steel or titanium. It is comparable with corundum (α-Al2O3), sapphire and ruby in hardness and can only be polished and finished with abrasives of superior hardness such as cubic boron nitride and diamond, in the form of powder, wheels, and compounds.