Sodium Feldspar also know as Soda Feldspar is generally a clean white mineral that sources sodium, alumina and silica along with some potassium and calcium. No actual materials have the ideal formula shown here, they all have some K2O and small amounts of other contaminants. Sodium Feldspar is a common raw material used in Glassmaking, Ceramics, and to some extent as a filler and extender in Paint, Plastics, and Rubber in Glassmaking, Alumina from Feldspar improves product Hardness, Durability, and resistance to chemical corrosion.