10 microns or less, % 92 Brightness 92 Oil absorption 18 Specific Gravity 2.65 Hegman Grind 7.0-7.5 PH 6.5-7.3 Chemical analysis, % Si 02 99.34 Fe2 03 0.03 A12 03 0.11 Ti 02 0.02 Ca O 0.025 Mg O+KO 0.042 Loss on ignition 0.18