AbstractThe performance of an energy‐dispersive x‐ray fluorescence (ED‐XRF) system for the analysis of silicate rocks was investigated in detail. Data are presented to demonstrate the selection of optimum excitation conditions for the major elements (Na‐Fe), analysed on glass beads, and the trace elements (particularly the Rb‐Nb group) analysed on powder pellets. Limitations in spectrum analysis due to overlap interferences are discussed and have largely been overcome using x‐ray profile fitting software. The results show that when operated under optimum excitation conditions, ED‐XRF spectrometry can routinely achieve a high degree of accuracy and precision in the analysis of a wide range of major and trace elements in silicate rocks. For many elements, 2s standard deviations are better than 2% relative. Limits of determination for many trace elements are in the r