This award provides one-half of the funding needed to upgrade an X-ray diffractometer used by the Department of Geology at the University of Illinois. The University is committed to providing the remaining funds needed. The improved x-ray diffraction system will be used by several research programs that need to identify the mineralogy of sedimentary rocks, which typically exhibit X-ray diffraction patterns with numerous and broad overlapping peaks. The instrument upgrade includes incident beam slits for better resolution and the automation hardware and software for diffraction profile fitting procedures (Rietveld refinement) that will allow accurate determination of diffraction peak intensities, positions and shapes. Current projects that will make immediate use of the improved capabilities include research on the origin of coal, carbonate diagenesis, paleoceanography, and the mechanism of mineral-water interactions.