Nuclear techniques applied to provenance and technological studies of Renaissance majolica roundels from Portuguese museums attributed to della Robbia Italian workshop

Artistic and historical examination of high-quality glazed terracotta sculptures displayed in various Portuguese museums point to their production in della Robbia workshop of Florence (Italy). A multitechnique analytical approach is applied for the first time to these sculptures, aiming to confirm their origin. Materials were analyzed using Instrumental Neutron Activation Analysis, Prompt Gamma Activation Analysis and X-ray Diffraction. The compositional results are similar to other della Robbia sculptures, suggesting a common origin for the raw material that was identified as carbonate rich marine origin marly clay. The applied firing temperatures was proved to be around 900 deg C. The differences found within each sculpture are explained by the production technique of assembling separate parts to produce these huge sculptures, and the clay pit heterogeneity. (author)