Rhyolite grinding-milling tools in focus: Assessing kinematics with the help of use-wear analysis

Past societies have used various raw materials for making grinding-milling tools (GMT). These included rhyolite, a hard volcanic rock with a porphyritic texture and pores, which is suitable for grinding. Thus far, no experiments have been carried out involving use-wear analysis on rhyolite grinding stones, and more specifically on Neolithic GMTs made of this raw material. Therefore, in this paper, we present an experimental program designed to investigate the development of wear from the grinding of einkorn wheat (Triticum monococcum) on rhyolite GMT replicas. To test the resulting observations, four GMTs found at the Neolithic site of Vchynice were used as a case study. However, the results of the experiments can be used to study these important artefacts in other geographic and cultural areas. The experiment has yielded several important findings relating to the kinematics of the tools and throws new light on their users. The orientation of the tool relative to the user can be distinguished based on the distribution of the use-wear traces. The study of the archaeological assemblage revealed that substances other than einkorn wheat, which was used for our experimental grinding, were processed on the Neolithic GMTs.