Skaill knives from the Ness of Brodgar: An experimental pilot study exploring their potential for functional and technological analysis

This paper presents the results of a pilot study exploring the biographies of Skaill knives from the Neolithic site of Ness of Brodgar (UK). Skaill knives are large sandstone flakes made from beach cobbles. We present an experimental study in which we replicated and used Skaill knives. A selection of ten archaeological Skaill knives was subjected to a detailed technological and functional analysis. Functional analysis of the experimental and archaeological tools was conducted both with a low power stereomicroscope and a high-power metallographic microscope. 3D models of the archaeological Skaill knives were made to better understand and visualise technological features and use-wear traces. These observations allowed us to link the flaked cobbles, frequently found in Neolithic Orkney, to the chaîne opératoire of Skaill knives. Regarding the production process, we were able to demonstrate that it seems likely that at least some of the Skaill knives were produced using bipolar percussion. Contrary to what was hitherto assumed, it seems unlikely that the Skaill knives were produced by dashing the stones on rocks, as the archaeological evidence points towards a more controlled method of production. The experimental work generally resulted in little to no polish development, but macroscopic features such as edge rounding and edge removals frequently occurred. The archaeological Skaill knives displayed diverse use-wear traces. Certain zones displayed heavy unifacial rounding, which most likely resulted from a scraping motion on an abrasive material. Other zones displayed extensive edge removals, which could either be linked to butchering activities or to contact with harder materials. Morphologically, these traces appeared to be linked to different zones on the Skaill knives. The extensively rounded zones more commonly appeared on the short sides of Skaill knives, when cobbles were split lengthwise. The edge removals tended to occur on the long sides of Skaill knives which were split along the width of the cobble. Although specific contact materials could not be assigned, the study revealed interesting insights into the biographies of these tools.