... Only no harder than Boron carbide and Diamond, friable, its girt is sharp, and Thermal conductivity4 Suitable for grinding Hard ... , shape, size, abrasive material, grain, grade, , and speed SpeciesCode No.colorfeaturesselectionbrown fused aluminaATanhigh rigidity, strong flexibility, ... for grinding Hard alloy, Optical glass, vitrify and other hard friable materials.Black silicon carbideCblack Harder ...