Mineralisation of ancient textiles: An archaeometric analysis of Etruscan textile fragments from the tombs of Perugia.

Ancient textiles do not appear often in the archaeological record, and when they do they might have undergone chemical alteration, allowing them to survive through time. This process of mineralisation, where the organic fibres have been replaced, fully or partially, by inorganic compounds, has been known to occur when the textile has been in contact with a metal. However, another, more rare type of mineralisation occurs in calcium-rich environments. The textile samples from the late Etruscan (2nd-1st century BCE) cemeteries of Strozzacapponi and Ponticello near Perugia, Italy, discussed in this thesis present such a case. This thesis aims to uncover the mineralisation process these textile fragments have undergone, using various archaeometric techniques: Confocal laser scanning microscopy, portable and benchtop micro-Raman, Fourier-transform infrared spectroscopy and X-ray diffraction. The analyses show that the main mineral components of the textile samples examined mostly consist of calcium carbonate (calcite) or gypsum. So far, no absolute cause could be determined. However, the use of travertine (a carbonate rock) as material for the cinerary urns might have had a significant influence on the mineralisation process, as well as the microclimate present within subterranean tombs. Furthermore, a recent hypothesis that the Etruscans could have added slaked lime to the contents of the urns is explored.