Italian Maiolica and Sgraffito pottery from Volterra: a non-invasive and non-destructive raman and XRF analytical investigation

This paper reports on the preliminary results of the ongoing research on Medieval and Renaissance ceramic corpus from a cistern placed under the Incontri-Viti Palace in Volterra, Italy. The potteries found in the cistern are dated between 14th and 16th centuries; this period is marked by the transition between the late Middle-Ages and the Renaissance, and it is characterized by the introduction of technological and stylistic innovations in glazed ceramic productions. The work is part of a wider research program which involves the study of Volterra from the Late Antiquity to the Early Modern Age, through the detailed characterization of ceramic finds. Among samples from Incontri-Viti Palace, thirty-three fragments were selected for this investigation based on shape and decoration, including Maiolica and Graffita (or Sgraffito) productions. Micro-Raman and X-ray fluorescence analysis were carried out on both glaze and body, providing – for the first time – the non-invasive and non-destructive characterization of Maiolica and Graffita productions from Volterra. The investigation allowed the discrimination among studied productions based on glaze components and colouring agents, identifying one main compositional group credibly linked to local workshops. The analysis of ceramic paste enabled differentiating Italo Moresca among Maiolica productions for the higher tenor of Ca, which is a marker of the technological innovation optimised for obtaining a creamy coloured paste.