Chemical composition (Wt. %)*

SiO₂

Al₂O₃

Fe₂O₃

TiO₂

CaO

MgO

Na₂O

K₂O

SO₃

Cl⁻

Loss of ignition

92.30

3.83

0.49

0.05

2.05

0.19

0.01

0.05

0.23

0.80

3.23