Characterisation of painting materials from Eritrea rock art sites with non-destructive spectroscopic techniques

Rock painting samples from Eritrean archaeological sites were studied by means of micro-Raman spectroscopy and proton-induced X-ray emission technique (PIXE). Hematite and manganese oxides/hydroxides were determined inr ed and black paints, respectively. Since colours do not contain carbon, the paintings cannot be dated with C-14. Moderate amounts of calcium carbonate or sulphate were also observed in most red drawings, while traces of phosphorus were found by PIXE only in a few red and black samples.