Calcium silicate is a food additive identified under the code E552 according to the international classification of food additives.

Synthetic or mineral anti-caking agent, used with colorants and in foods in tablet, lozenge, and dragee form. No known risks.

Silicon dioxide, or silica, is a chemical compound with the formula SiO2. It is a colorless solid present in abundance in the natural environment and in various living beings.