The elemental analysis of geologic samples such as rocks, minerals and coal ash is a complicated task because of their wide, complex compositional range. Energy dispersive x-ray fluorescence (EDXRF) can provide a rapid, accurate and precise way of analyzing geologic samples. Two approaches to reducing EDXRF intensity data to elemental concentrations are the empirical approach and the fundamental parameters (theoretical) approach. Empirical methods require numerous standards within restricted compositional ranges so can become complex, time consuming and, therefore, expensive if diverse suites of samples are to be analyzed for many elements. Fundamental parameters, on the other hand, requires knowledge of physical constants such as mass absorption coefficients, jump ratios and fluorescent yields, and only one matrix independent standard to calculate a calibration constant for each element making it an ideal approach to the analysis of diverse geologic samples.