CAB-O-SIL® M-5 untreated fumed silica is a synthetic, amorphous, colloidal silicon dioxide that is generallyregarded as unique in industry because of its unusual particle characteristics. CAB-O-SIL fumed silica?sextremely small particle size, its enormous surface area, its high purity, and its chain-forming tendencies set it apart in a class of its own. CAB-O-SIL fumed silica is a light, fluffy powder that is white in appearance and is used in many applications and a variety of industries.