The first archaeometric characterization of Roman millstones found in the aquileia archaeological site (Udine, Italy)

An archaeometric study of all the Roman millstones preserved today in the National Archaeological Museum of Aquileia, the ancient capital of the X Regio Augustea -'Venetia et Histria' located on the Friuli plain (northeastern Italy), has been recently envisaged to define their geological-geographical provenance. We present here the results of the first step of the research, which is aimed at characterizing all of the definitely allochthonous lithologies. In order to carry out petrography on thin-section and geochemical analyses, 10 small samples were picked out directly from Pompeian-style millstones (catilli and/or metae) and rotary querns. Five different lithologies originating in various Italian regions were recognized: eight samples consist of pale- and dark-grey lavas from the Venetian Volcanic Province, Vulsini Volcanic District (Latium), Etna Volcano and Pantelleria island (Sicily), whereas two samples were shown to be made of green garnet-bearing schists (pietra ollare) from the Western Italian Alps. The presence of Alpine pietra ollare in northeastern Italy, used to produce pots and food containers, was established for numerous classical findings at Roman and Middle Age sites, but the analysed items represent the first evidence for the utilization of this kind of stone to produce mills during the Roman epoch.