Flint (Silica) (SiO2) - Basic glass-former in both bodies & glazes, increases hardness and resistance to wear. Used to remedy crazing in glazes when added to either glaze or clay. In glazes it will reduce thermal expansion; in bodies it will promote thermal expansion. Warning: Contains Free Silica. Do not breathe dust. Prolonged inhalation may cause delayed lung injury (silicosis). Follow OSHA safety standards for handling. CAS#744-44-2