Standard Specifications. · Silica as SiO2 : 65.5% (+/- 1%) · Alumina as Al2O3 : 18.5 % (+/- 0.5%) · Potassium as K2O : 11 % (+/- 1%) · Sodium as Na2O : 2.8 % (+/- 1%) · Ferric Oxide as Fe2O3 : 0.15% Max. · Loss on Ignition :1% Max. · Moisture :2.5 % Max. · Particle size +200 Mesh : 3% Max.