¡¡It is brown and features toughness and impact strength.It can bear high pressure.Its knoop's hardness is 1800-2200 kg/mm2 .It is suitable for making bonded and coated abrasive tools,wet or dry blasting,super precision grinding and polishing,making super refractory materials,grinding carbon steel,alloy steel,malleable cast iron,hard bronze and semi-conductor materials.
