By using a transmission electron microscope (TEM) equipped with an energy dispersive electron-microprobe analyzer, genetical relationships between micro-morphology and chemical composition of kaolin minerals were investigated.
The TEM observation revealed that the kaolinite specimens, which show a 7Å basal reflection in X-ray diffraction diagram, are commonly mixtures of particles with various morphology such as film, hexagonal plate and long tube (Table 1). The chemical compositions of these kinds of particles are different from one another as shown in Fig. 1 and 2. Triangular plot of SiO2, Al2O3 and ΣFeO of the Kibushi clay (No.7 in Fig.2) shows limited chemistry of each morphology with slight overlap that SiO2 content of the film of indefinite primitive form is less than that of hexagonal plate, whereas, ΣFeO is lower in the latter. However, the chemistry of the Austria kaolin (No.5 in Fig.2) shows the reverse trend in SiO2 content. This reverse trend might suggest the difference in the source material.
