RAMAN MICROSCOPY OF SOME KAOLINITE CLAY-MINERALS

Raman microscopy has been used to study various samples of clay minera ls in the OH stretching region 3500-3800 cm(-1) using 633 nm excitatio n (He/Ne laser) and in the 200-1200 cm(-1) region using 780 nm excitat ion (diode laser). Various samples of kaolinite, dickite, nacrite and halloysite were examined. The use of a Ra?nan microscope has made it p ossible to record spectra of various crystal orientations of samples o f dickite, nacrite and halloysite. Remarkable differences are observed between spectra recorded from the different faces of the crystals. As signments are suggested for bands observed in the OH stretching region . The complex spectra observed in the lattice mode region of kaolinite and dickite are discussed.