Application of Electron Microscopy to the study of smectites and zeolites

Electron beam techniques namely Scanning Electron Microscopy (SEM), the closely related Electron Probe Microanalysis (EPMA) and Transmission Electron Microscopy (TEM) find ample applications on the characterization of various types of geological materials including clays. They provide morphological, structural and chemical information down to the atomic scale. The principal advantage of the electron microscope over the light microscope is the much improved resolution, due to the very low wavelength of the energetic electron (<1 Å) compared to the visible light, which is employed in the optical microscope. An additional advantage of the microbeam instruments is the generation of X-rays from excitation of the samples when bombarded by electrons (Pownceby & Macrae, 2009). For these reasons the microbeam techniques have been employed successfully in the study of clay materials during the past 45 years.