Typical Chemical Analysis SiO2 52.0% CaO 0.5% Loss of Ignition 15.0% A12O3 30.0% K2O 1.2% Moisture Below 33.0 % Fe2O3 1.3% Na2O 0.2% Brightness 90.0 TiO2 1.0% MgO 0.5% Fired Shrinkage at 1200°C 8.0 ?? 11.0% Water Absorption at 1200°C 11.0% Dry Modulus >15 kgf/cm2 Clay Residue (63µ) 10.0% Chromatic coordinate (L Value) 90 point Whiteness Index (WI) 60 point