LAUSR

Despite their high potential for understanding past human behaviours, the study of grindstones is limited in the literature compared with other forms of lithic tools. This paper reports the combination of optical microscopy and Raman microspectroscopy for understanding the uses of a selection of six grindstones from the post-Howiesons Poort layers at Sibudu, South Africa, dating to 58,000 years ago. Five of the specimens exhibit numerous red haematite stains which imply red ochre processing. Nevertheless, each artefact seems to have been used for a specific task. For example, the smallest grindstone was used for a combination of tasks—ochre, bone, and organic matter processing. The distinction between use residues, sediment contamination, secondary mineral formation, modern contamination, and components included in the sandstone that the grindstones are made from is discussed.