Chemical Analysis

% by Weight

Silicon as SiO₂

40 - 42

Magnesium as MgO

20 - 26

Potassium as K₂O

10 - 11

Aluminum as Al₂O₃

9 - 11

Iron as Fe₂O₃

3 - 11

Loss on Ignition at 1000˚C

1 - 3