Shiny by Design: Establishing Diagnostic Criteria for Intentional Burnishing on Prehistoric Bone Artifacts

The identification of intentional burnishing on prehistoric osseous artifacts remains a persistent methodological challenge. Bone surfaces are highly reactive and readily record microwear traces but are susceptible to taphonomic alteration. This study investigates how the use of different burnishing materials affects the morphology of bone surfaces and the formation of diagnostic microwear traces to develop a methodologically grounded classification for identifying intentionally burnished surfaces on archeological osseous artifacts. Experimental observations are evaluated in relation to existing knowledge of use-related, manufacturing, and postdepositional surface modifications. The analysis is based on a microwear framework that integrates multiscalar observations (low- and high-magnification microscopy and scanning electron microscopy) with quantitative three-dimensional surface texture analysis. Both microscopy and quantitative data derived from confocal microscopy reveal clear differences among bones burnished with different agents, highlighting agent-specific topographic patterns. The experimentally derived reference dataset was subsequently applied during microwear analysis of selected prehistoric bone points from Lake Lubāns (Latvia) and the Wiele 33 site (Poland) to assess the analytical applicability of the proposed protocol. The results of our study demonstrate the diagnostic potential of the created classification of wear traces to distinguish intentional burnishing on archaeological osseous artifacts and to discriminate between intentional, use-related, and taphonomic surface modifications.