... 3.More than 90% exported Black silicon carbide stone polishing1.High purity,SIC:98%min 2.FEPA, ... made of it are suitable for working on cast iron, non-ferrous metal, rock, leather, rubber, etc ... is the main raw materials of quartz sand , stone sand and petroleum coke. 2.It is made ... hardnessBlack silicon carbide abrasives are suitable for working on cast iron, non-ferrous metal, rock, leather, rubber, etc ...