The use of diatomaceous earth in industry as filtering aids, mineral fillers, catalyst carriers, chromatographic supports, and paint additives is well documented. The diatomite matrix is well suited to x-ray analysis, but this application has not been cited in the literature. In our laboratory, x-ray fluorescence spectrometry has been used to support the analytical needs of diatomite product development. Lithium borate fusion and pressed powder techniques have been used to determine major, minor, and trace elements in diatomite and synthetic silicate samples. Conventional matrix correction models and fundamental parameters have been used to reduce x-ray measurements to accurate chemical analyses.