Flint (ST9) (SiO2)
Flint, sometimes silica, quartz, silicon dioxide - when it comes to glaze recipe it is usually Flint = very fine ground SiO2. Sometime rough silica (quartz) can be used in kilns on the shelfs to prevent wessels from sticking. Melts at 3119°F and combines under heat with variety of fluxes to make lower temperature glaze. It increases the termal expansion in clays and decreses the termal expansion in glazes. An increase in the silica content of the glaze will raise the maturing temperature.