[en] Full text: High-quality hot-filament chemical vapor deposition (CVD) diamond surfaces (as grown on polished Si wafers) were subjected to tribomechanical wear by rotating a disk under the friction of a diamond coated ball in various environments. We investigated the resulting wear tracks and their vicinity by utilizing near edge x-ray absorption e structure (NEXAFS) spectroscopy and x-ray emission spectroscopy at the C 1s- absorption edge. Our NEXAFS spectra have both high energy resolution (0.05eV steps) and unprecedented high spatial resolution (10μm spot size), thereby allowing us to resolve changes within individual wear- tracks. We find that the degree of chemical modification in the wear tracks strongly depends upon the type of environment during the wear process. Moreover, the effect of wear depends on whether the initial surface is smooth (polished Si-wafer substrate side) or rough (the as-grown vacuum side). We discuss the nature of chemical modification that can be determined by certain spectral signatures of NEXAFS spectra from model compounds from literature. In particular, we address the question to which degree graphitization and other phase transformations, such as amorphization and ex situ reactions, take place. We discuss the features and advantages that this technique has compared to photoelectron emission microscopy