ORIGINAL PAPER Compositional analysis of Tuscan glass samples: in search of raw material fingerprints S. Cagno & K. Janssens & M. Mendera Received: 31 October 2007 / Revised: 31 January 2008 / Accepted: 6 February 2008 # Springer-Verlag 2008 Abstract SEM-EDX quantitative analyses were performed on 91 samples of vessel glass originating from a number of sites throughout Tuscany. A comparison with Venetian glass data is made in order to evaluate differences in glassmaking materials. The compositions of the samples provide clues about the different raw materials used in relation to recipes that changed slightly during the period covering the late Middle Ages to early Renaissance. Two kinds of ash used as a fluxing agent were identified, one of which is of east Mediterranean origin while the other is likely to be Spanish. Two types of silica sources were also found. One of these was recognized as being quartziferous river pebbles, while the other is proposed to be local sand. Keywords Archaeometry/fine arts . Glass . Tuscany . Venice . Electron microprobe . X-ray spectroscopy (EDX) . SEM-EDX Introduction Glass in Italy in the medieval–Renaissance period was a luxury product that spread throughout the entire peninsula, starting from a limited number of locations with an established tradition in glass manufacture. While Venice was undoubtedly the most important center of glass production, the remains of glass workshops have been uncovered by archaeologists in other areas of Italy too, such as Tuscany, demonstrating that there were workshops in which all of the phases of the production chain were executed. A number of glass produc- tion sites located in the municipality of Gambassi Terme were the focus of a study where attention was mainly devoted to raw materials, production indicators and the final glass fragments that had been excavated [1–4]. The aim of this work was to determine whether it is possible to identify the raw materials used in glass production by considering the major elemental composi- tions of a set of glass fragments excavated at these sites. Ninety-one samples of glass fragments from different sites located in Tuscany were analyzed via scanning electron microscope–energy dispersive X-ray analysis (SEM-EDX) in order to (a) compare the glass compositions encountered at the Tuscan production sites to those of the other sites and (b) compare Tuscan and Venetian glass compositions. Samples of finished glass vessels from Tuscan production sites were analyzed together with glass originating from other Tuscan locations, while comparisons were also made with data on Venetian products. Raw materials used for glassmaking Since the fluxing agents used for glass production in Italy of the Middle Age were imported ashes, trade in and the transport of raw materials had an important impact on the development of the glass industry, and on the resulting glass composition. It is reported that in Italy coastal plant ashes were imported from the Eastern Mediterranean (Levantine ash) [5] or from Spain, from the region of Alicante [6]. These two types of ash resulted in different Anal Bioanal Chem DOI 10.1007/s00216-008-1945-8 S. Cagno (*) : K. Janssens MITAC 4, Department of Chemistry, University of Antwerp (UA), Universiteitsplein 1, 2610 Antwerp, Belgium e-mail: simone.cagno@ua.ac.be M. Mendera Department of Archeology, Università di Siena, Via Roma 56, 53100 Siena, Italy