1. National Research Council, Institute for Conservation and Valorization of Cultural Heritage, Sesto Fiorentino (FI), Italy
2. Department of Earth Science, University of Florence, Florence, Italy
3. LAMA – Laboratory for Analysis of the Ancient Materials, DACC, University Iuav of Venice, San Polo Venice, Italy
4. Department of Physical Sciences, Earth and Environment, University of Siena, Siena, Italy
5. Department of Earth Sciences, University of Pisa, Pisa, Italy