Lo scavo dell’Allumiera di Monteleo. Nuovi dati per la produzione dell’allume alunitico nel tardo Medioevo

The presence of alunite and "natural alums" is documented in different areas of the Colline Metallifere district, where the main ore deposits are located. It is here that the research conducted by the University of Siena has identified various alum mines (open casts and galleries) and the remains of some important alum productive sites (allumiere) dating back to the 15th-16th centuries. The investigation of the Monterotondo Marittimo district in particular, started in 2004 with an accurate topographic campaign, has produced valuable indications regarding the settlement dynamics and the exploitation of natural resources. From 2008 to 2016, the excavation of an early Modern Age production site located in the heart of an alunite deposit, the "Allumiere di Monteleo", provided an exceptional opportunity to explore the various steps involved in the processing of raw materials, and highlighting the versatility of such production centers. The research has offered us the possibility to cross different sources (archival; archaeological; geological; cartographic) to investigate a wide diachrony of the use of raw materials. Starting from the evaluation of these systems of sources we will propose here a diachronic rereading of the valorisation of natural resources in the light of the data coming from the most recent campaigns on the production complex of the Allumiere di Monteleo.