This paper presents new developments on the provenance study of lapis lazuli started by our group in 2008: during the years a multi-technique approach has been exploited to obtain minero-petrographic characterization and creation of a database considering only rock samples of known provenance. Since the final aim of the study is to develop a method to analyze archeological findings and artworks made with lapis lazuli in a completely non-invasive way, ion beam analysis techniques were employed to trace the provenance of the raw material used for the production of artifacts. Continuing this goal and focusing the analysis on determination of more significant minero-chemical markers for the provenance study of trace elements in different minerals, the method was extended with the use of micro X-ray fluorescence (µ-XRF), to test the potential of the technique for this application. The analyzes were focused on diopside and pyrite in lapis lazuli samples of known provenance (Afghanistan, Tajikistan, and Siberia). In addition, µ-XRF data were compared with micro proton-induced X-ray emission (µ-PIXE) results to verify the agreement between the two databases and to compare the analytical performance of both techniques for this application.

Ion beam analysis (IBA) techniques are a powerful analytical tool used to investigate the composition and structure of precious materials principally because they can be applied in atmosphere. Thus, the sample can be analyzed as is, and heating and charging effects are strongly diminished. Since IBA measurements can be made with low ion currents and acquisition time, the damage risk is limited. At the microbeam line of the LABEC laboratory, it is possible to exploit the potentials of IBA techniques in an external set up to reconstruct the distribution maps of all the detected elements over the analyzed area with spatial resolutions as low as 10 μm. This is an important feature when objects with inhomogeneous structures—on a scale of hundred microns or so—are investigated, as happens in some cases with artworks. The detection set up installed on our external microbeam allows us to use different IBA techniques simultaneously. Thus, in a single measurement run, it is possible to obtain complementary information on both sample composition and structure. Some applications to works of art are presented here as examples of the analytical capabilities of the external scanning microbeam in the cultural heritage field.