Alumina (Al2O3) is our secondary glass former in ceramic glazes. It has a very high melting temperature 2200°C. That’s 900°C over cone 10.
Alumina acts as a glaze stiffener. It helps to keep our glazes from running off the pot.
The generic formula for the clay mineral is Al2O3•2SiO2•2H2O« Back to Glossary Index