Synchrotron FTIR micro-spectroscopy applied to the study of polished serpentinite artefacts: a non destructive analytical approach

Serpentinite is one of the most frequently raw materials used to produce polished stone artefacts in prehistory. Several conventional analytical techniques can be applied to identify the serpentine minerals but their application generally requires a powdered sample. This implies that the artefacts to be analysed must be damaged, grinded and the possibility to analyze a mixture of different serpentine polymorphs is high. The use of spatially resolved techniques is therefore a necessity to overcome this problem. Several thin sections of serpentinitic rocks and prehistoric axes have been analyzed by Synchrotron Fourier Transform InfraRed Micro-Spectroscopy while some spectra were acquired directly on specific points of polished stone artefacts and allowed recognizing the different polymorphs of serpentine minerals without causing any damage to the objects. The results comfort the infrared micro-spectroscopy technique as a performing tool for the characterization of archaeological lithic material.