Characterising thin mineral layers on heterogeneous media is a significant challenge in archaeometry. Nevertheless, obtaining such geochemical and mineralogical data can, in many cases, provide valuable information about the original raw-material procurement strategies and document the chaîne opératoire leading to the finished object. In this contribution, we report on the geochemical analysis of a thin layer of red mineral pigment found on a skull from the Mesolithic burial of Campu Stefanu, Corsica. A proton ion beam analysis was conducted at the New AGLAE facilities (Palais du Louvre, Paris) to determine major, minor and trace element compositions. Contribution from the pigment's elemental composition is statistically differentiated from that of the bone and the sediment. Furthermore, the composition of the pigment is shown to be compatible with that of iron-oxide rich mineral blocks found within the mortuary deposits.