Ion beam analysis has been used to investigate Danish archaeological flint artifacts. Hydrogen profiling by means of ¹⁵N was used to study water uptake, flaking properties, and the nature of glossy wear traces. Good correlation between changes in hydrogen profiles and the material worked with a given tool was found. Proton-induced x-ray emission, Rutherford back scattering and electron microprobe analysis were used for investigations of brown patination of flint. The patination was found to be caused by iron penetrating the boundaries between quartz grains of the flint while individual brown spots contained excess concentrations of iron, manganese, or iodine. See also AATA 20-810. -- AATA