Abstract
Operation of a scanning electron microscope in the backscattered-electron/low-vacuum mode instead of the conventional secondary-electron/high-vacuum mode transforms the SEM into a powerful general-purpose tool for mineralogy and the other earth sciences. The technique has two major advantages over conventional SEM operation: (1) High-quality atomic-number contrast images are produced, providing information that is much more useful than that normally obtained from an SEM. Compositional information dominates topographic information in the images so that most phases are clearly differentiated. (2) The technique is very simple. No conductive coating is required, even at high accelerating voltages. Drill core, hand specimens, mill products, polished sections, or porous wet samples can all be imaged directly as received, and it is possible to display an image and an X-ray spectrum within a minute of receipt of the specimen.
