Description CAS#: 7631-86-9 | Formula: SiO2 | Specifications: Assay 99.7 % - Min, Iron 0.005 % Max, Loss on ignition (1750 F) 4.5 - 10.0 %, pH (5% slurry) 5.5 - 7.0 pH, Surface area 430-530 m2/g