A semiquantitative X-ray diffraction method to determine mineral composition in stream sediments with similar mineralogy

A semiquantitative X‐ray diffraction procedure has been developed that can be used to acquire reproducible mineralogic data from geographically unrelated stream‐sediment samples having similar mineralogy. Weight percentages for quartz, total‐feldspar, and total‐clay can be determined by direct comparison of intensities with standard‐mineral mixtures of known weight percent. Matrix effects and mass‐absorption differences are circumvented by taking the ratio of peak‐intensity, in counts per second, for quartz relative to that of other minerals being quantified. Mineral percentages generally are reproducible to within 10 percent.