Ceramic findings from the archaeological site at Aiano-Torraccia di Chiusi (Siena, Italy): a multi-analytical approach

In 2005, the remains of a Roman villa, dating from the early fourth to the sixth centuries ad, were discovered at the archaeological site of Aiano-Torraccia di Chiusi (Siena, Italy). After being abandoned in the sixth century ad, the complex was occupied by a group of Ostrogothic or Lombardic artisans in the period between the sixth and the seventh centuries ad. Many ceramic remains (coarse pottery and red slip ceramics) from the first to the seventh centuries ad have been discovered on this archaeological site. These findings have been analysed using different analytical techniques (optical microscopy (OM), X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscope-energy dispersive spectroscopy (SEM-EDS), attenuated total reflection Fourier transform infrared (ATR-FTIR), and micro-Raman in order to characterize the ceramic body, the coating, the temper, and to investigate the compositional relationship between the different kinds of ceramics. The use of different techniques on the same samples yielded information at different scales. OM and SEM-EDS yielded interesting information on the coarse pottery: the analyses performed on some minerals and rock fragments suggest that stone tesserae from the Roman villa (in the form of numerous marble fragments) were used in the production of this pottery. Bulk analyses (XRD and XRF) and subsequent micro-analyses (SEM-EDS, ATR-FTIR, and micro-Raman) of the red slip pottery revealed clear chemical, mineralogical and textural differences: some ceramics (the TCC sample group) typically have a Fe-enriched coating while others (the INGR sample group) present a clear difference in grain size but no chemical or mineralogical differences between the ceramic body and the coating.