Understanding how obsidian was obtained in prehistoric times is an important challenge for archaeological sciences. This aphyric volcanic magmatic rock is a key marker of exchanges, contacts, and the movement of human groups during Prehistory. Cann and Renfrew demonstrated in 1964 that elemental analyses provided geochemical fingerprints that could be used to study the provenance of obsidian. Since this pioneering study, numerous geochemical methods (EMPA, INAA, LA-ICP-MS, PIXE, SEM-EDXS) have been deployed to measure major, minor, and trace elements in obsidian. The advent of pXRF was a complete revolution in Archaeometry that profoundly changed the analytical strategies put in place to study the provenance of this precious raw material. This presentation will examine the success stories of pXRF through several examples. In many ways, this method seems ideal: in addition to its portability, it is easy to use, fast, non-invasive, and particularly effective for the measurement of diagnostic elements, and can be adapted to numerous chronological periods and geographical areas. However, despite the many advantages of this method, it is important to discuss the calibration of the equipment and the accuracy and precision of the data produced. In addition, the size and/or thickness of the pieces analysed can have a significant impact on the results.