Pottery vessels and technology of “colouring materials” in the central-western Mediterranean (Sardinia, Italy) during the Middle Neolithic: An interdisciplinary approach combining use-wear and chemical-physical analysis

Despite the wide occurrence of colour deposits adhering to the surfaces of several artefacts (specifically, pottery and lithic tools) in Early and Middle Neolithic sites of the Western Mediterranean regions, the chaîne opératoire of colouring materials has not been frequently addressed by systematic techno-functional studies. Particularly, the relationship between pottery function and coloured contents is generally overlooked. In this paper, the use of colouring materials by Middle Neolithic (4500–4000 cal BC) societies in Sardinia (Italy) is investigated, focusing on the archaeological findings from the open-air settlement of Su Mulinu Mannu-Terralba (OR). The aims are to identify the kind of materials, to provide a first assessment of the production methods and to evaluate the role assigned to pottery vessels in processing, handling, and using colouring materials. For these purposes, we apply an interdisciplinary approach, combining analysis of lithic artefacts, use-wear analysis of pottery, archaeometric identification of the chemical and mineralogical composition of geomaterials and colour deposits on artefacts by PXRD, ATR-FTIR and SEM-EDS analyses, and biomolecular analysis of organic residues from pottery by GC-FID and GC–MS. This study reveals the use of haematite-rich ochre as the exclusive red colour-producing geomaterial, processed in situ with basalt macro-tools. Use-wear associated with ochre deposits on pottery vessels points to the selection of some bowls and jars, respectively for processing and storing ochre as the single content or, possibly, as an ingredient of composite products. However, based on our data, the addition of organic materials to ochre is not definitely demonstrated. Beside the preparation of pigments, the occurrence of ochre as content in pottery vessels could be related to a broader range of purposes, encompassing both the technical and the symbolic realm. Overall, these results provide insights both on the technology of “colouring materials” and the use of pottery in the practices of Middle Neolithic groups.