A band at 1.40 nm (Mg 20 °C treatment) that shifts to 1.60–1.70nmafterMg–eg treatment due to swelling indicates the presence of discrete smectite. In addition, the combination of the peaks at 1.40 nmafterMg-20 °C andMg–eg, and the collapse of the peak from 1.10 to 1.00 nm due to the dehydration after a K-saturation followed by heating correspond to vermiculite.