A study of stone tools from the Roman site of Volubilis in central Morocco has revealed that the material used to make them was specifically selected to improve the function of each object.
The UNESCO World Heritage Site of Volubilis was a flourishing Roman urban centre until the early 4th century BC, and stone implements connected to industry and commerce have been found in a number of the workshops and houses still standing at the site.
Now, researchers from the University of Texas at Austin have carried out geochemical analysis of grain millstones, olive millstones, and dough mixing vats from the site, as part of the Urban Economy of Volubilis Project. They discovered that each of these tools was made of a particular type of rock: for the grain mills, versicular basalt, a volcanic stone containing sharp-edged pores which would have provided fresh edges for grinding the wheat into flour as the stone was worn down; for the olive mills, clastic fossiliferous limestone, containing fragments of small fossil shells and other rocks, and for the dough mixers, a limestone without any clastic material or fossils.
The analysis also discovered that all of the stone used to make these tools was sourced near Volubilis, and it appears that each rock type came from a single location. This might indicate the presence of a single supplier for each of these stone types, meeting the demands of all of the local people and taking advantage of clear shared preferences among both professional craftspeople and household producers. The results of the study have recently been published in the Journal of Archaeological Science: Reports.