An integrated Raman and petrographic characterization of Italian mediaeval artifacts in pietra ollare (soapstone)

• DOI: 10.1002/jrs.4414
• Publication Date: 2013-12-18T06:14:37Z
• Authors: Chiara Baita; Pier Paolo Lottici; Emma Salvioli‐Mar...; Peter Vandenabeele; Mauro Librenti; Fabrizio Antonelli; Danilo Bersani
• Keywords: Greenschist; Ultramafic rock; Talc; Tremolite; Tourmaline; Archaeological Science

Ten fragments of pots made by pietra ollare (basic and ultrabasic metamorphic rocks belonging to greenschist facies) found in the archaeological site Crocetta di Sant'Agata Bolognese (Bologna, Italy) have been studied characterize them define their provenance. The fragments, dated between 9 th 10 century AD, show traces blackening from fire, indicating use these findings as fire. extensive a non‐destructive technique, Raman spectroscopy, both laboratory portable forms, for provenance analysis artifacts has evaluated. Micro‐Raman spectroscopy was used detailed study main components, identify secondary minerals distribution mineral phases samples. samples schistose texture, are fine grained consist mainly talc chlorite, subordinate carbonates, oxides serpentine. Olivine is rare. Based on mineralogical composition, material can be defined chlorite carbonate talc‐schist. Our may assigned magnesite‐bearing talc‐schists. alpine areas origin this lithotype Valtellina, Valchiavenna Val Bregaglia. In particular, we hypothesize that Valchiavenna, which had great commercial importance Middle Ages. Further measurements, obtained with spectrometer, directly quarry near Chiavenna, support our hypothesis. Copyright © 2013 John Wiley & Sons, Ltd.