Element Percentage by weight/unit / %
SiO2 60.75
Al2O3 24.15
Fe2O3 2.51
CaO 1.56
MgO 2.54
Na2O 3.63
K2O 0.65
SiO2/Al2O3 2.52
SiO2+ Al2O3 84.90
LIO 5.21

LOI: Loss on ignition
Table 1: XRF analysis of the clay-Na sample.