4 samples were analysed for their relative clay mineral content. Glass smear slides were prepared and measured on a Philips X'Pert Modular Powder Diffractometer at the University of Münster, equipped with a Cu anode (1.5405 Å) and operated with the following settings: 45 kV voltage, 40 mA current, 0.02°θ step size, 1 s per measurement step, 3-50°2θ measuring range, 30 runs per sample, and no sample rotation. Note that the data obtained via this analysis is not quantitative.