Kieselguhr, a diatomaceous earth (diatomite) is a form of silica composed of the siliceous shells of unicellular aquatic plants of microscopic size. Kieselguhr is heat resistant and has been used as an insulator, as a component in toothpaste and as an abrasive in metal polishes. In the chemical industry, it is also used as a filter to clarify syrups and sugar and as a filling material in paper, paints, ceramics, soap and detergents.