Fig. 3 X-ray diffraction diagrams from sorted biotite and related clay minerals pseudomorphs. (A) C4 saprolite. Transparent biotite mica flakes; (B) C4 saprolite. Pseudomorph after biotite; (C) G1 saprolite. Pseudomorph after biotite. M–V = mixed layer mica–vermiculite, K = kaolinite. Peak values in angströms