Major

oxides

Sample name

Cru_a

Cru_b

Cru_c

%MgO

0.03

0.02

0.04

%Al₂O₃

37.61

36.82

30.72

%SiO₂

55.82

57.81

60.57

%K₂O

0.35

0.40

0.89

%CaO

0.09

0.08

1.20

%TiO₂

1.70

1.96

1.06

%MnO

0.95

0.10

0.85

%Fe₂O₃

0.08

0.06

0.05

Loss of ignition

3.35

2.74

4.56