WHITENESS : 96% +/-2 SILICA SiO2 : 55 - 57% MAGNESIA MgO : 28 - 30% ALUMINA AI2O3 : 0.50 - 1.50% IRON Fe2O3 : 0.5 - 0.8% CALCIUM OXIDE CaO : 4 - 6% LOSS ON IGNITION : 4 - 6% BULK DENSITY (gm/ml) : 0.45 - 0.55% Ph : 8-9 MOISTURE : 0.4 - 0.6% SPECIFIC GRAVITY : 2.7 - 2.8% RETENTION ON 500 MESH : 0.5%