Fumed silica is Produced by a flame hydrolysis of volatile silicon compounds, fumed silica serves as an additive to various solids, powders, liquids and coatings. Also known as pyrogenic silica, amorphous silica and silicon dioxide, fumed silica consists of submicron particles that move between larger particles, creating a surface layer that acts as a lubricant. Consequently, fumed silica is often used as an anti-caking agent. Its ability to increase viscosity also makes fumed silica a popular choice as a thickening agent.