Characterisation of ancient mortars from the S. Niccolò archaeological complex in Montieri (Tuscany – Italy)

• The study of the mortars allowed us to identify 5 principal building phases.
• Metallurgic slags, cocciopesto and glasses are visible in the mortar aggregate.
• The metallurgic slags give to the binder a greater hydraulicity.
• Argentiferous minerals are present in the aggregate of some mortars.

The object of the present work is the archaeometric study of the mortars from the S. Niccolò archaeological site in Montieri (Tuscany – Italy). The petrographic, mineralogical and chemical characterisation of the samples was obtained by the use of multi-analytical techniques (OM, XRD, SEM–EDS, XRF). The knowledge of the constitutive materials allowed us to understand the different production technologies and highlighted the use of materials with hydraulic behaviour, such as metallurgical slags and cocciopesto. The compositional analogies and differences among the samples contributed to the reconstruction of the building phases, favouring the reading of the history and the evolution of the site over time.