A ‘Family of Wear’: Traceological Patterns on Pebbles Used for Burnishing Pots and Processing Other Plastic Mineral Matters

The development of technologies related to plastic mineral matters (PMM), including clay, mud, and plaster, represents a major step in cultural evolution because of their important repercussions for food processing, storage, transportation, construction, and symbolic expression in past human societies. This paper aims to illuminate the chaînes opératoires employed in the transformation of PMM and highlight early evidence for these technologies in the archaeological record. Our focus is ‘ad-hoc’ (or non-manufactured) ground stone tools used in finishing operations. Specifically, we discuss pebbles and cobbles employed to regularize, smooth, or burnish clay and mud-based products. Because these tools consist of unmodified rocks, recognizing and understanding the traces developed through use is essential for their identification. This is a pilot study that draws on experiments, ethnographic studies and quantification via confocal microscopy to assess the variability of use-wear developed on mud and clay processors. Extra attention is placed on micro-polish, not only because this type of wear has been seldom described before for such tools, but also because it appears to be highly diagnostic. We suggest that the variability observed can be described as a family of wear, that is, a range of recurrent use-wear characteristics associated with the processing of PMM. We analyze two collections associated with different chrono-cultural contexts: the Late Natufian site of Hilazon Tachtit in the Southern Levant and the Late Neolithic site of Kremasti-Kilada in Greece. At both sites, the identification of processors of PMM provides pivotal data to understand the relevant chaînes opératoires, assess the emergence and development of these technologies, and also explore symbolic behaviors.