Source: http://ctmpotterssupplies.co.uk/ceramicmaterialsglossary.html
| Na2O | K2O | Al2O3 | SiO2 | LOI |
| 7 | 9.10 | 24.9 | 56 | 3 |
From CTM:
K2O 9.1%, Na2O 7%, Al2O3 24.9%, SiO2 56%
More fusible than feldspar, it has lower silica and higher soda and potassium levels and so can be used a lower melting temperatures. Important for use in vitreous bodies.