1.White corundum FEPA P grit 2. for making sanding cloth, sanding paper, abrasive jumbo ... 99.45%Na2O 0.26%SiO2 0.13%Fe2O3 0.04% Physical Properties:Color WhiteShape Angular edge sharpCrystal Form Alpha aluminaSpecific ... .95Hardness 2150 Knoop scaleMagnetic Material 0.0025% Macrogrit Sizes Available (P):12, 16, 20, 24, 30, 36, 40, 50, 60, 80 ...