Abstract: A method for quickly and reliably identifying the lithological layer of an excavated material, which includes the steps of: a) analysing a specimen of the excavated material using X-ray fluorescence spectroscopy to determine the mass concentration of each of the inorganic chemical elements contained in the specimen, step a) being performed on n different surfaces of the specimen in order to determine n mass concentrations of each of the inorganic chemical elements contained in the specimen, with n being a whole number greater than or equal to 2, b) calculating the mean of the n mass concentrations of each of the inorganic chemical elements contained in the specimen and the standard deviation of this mean, c) classifying each of the inorganic chemical elements contained in the excavated material according to certain criteria for the mean n mass concentration, and d) identifying the lithological layer of the excavated material based on the classification performed during step c).