... corundum, brown aluminium oxide, dull grain shape, top high toughness Description:AETL is ... alumina trigonal systemSpecific Gravity 3.92Hardness 2090 Knoop scale, 9.0 Mohs scaleMagnetic Material 0.0076%Grain Sizes Available (F ... , 60, 70, 80, 90, 100, 120, 150, 180.Grain Size Distribution :Upon ANSI B74.12-2001, FEPA-Standard 42 ... artificial corundum brown fused alumina dull sandblasting abrasive grain