Nepheline Syenite – K2O3Na2O4Al2O39SiO2 (m.p. 2200o F/1200o C) is a soda feldspar used frequently in clay bodies and glazes. Its unique characteristic is: the molecular equivalence of K2O and Na2O is greater than a typical Soda or Potash feldspar in relation to the Silica content. It can be used in a clay body when lowering the maturing temperature of the body is required. In a glaze, it can reduce glaze defects such as crazing and increase the working range of a glazes cone 011-5.