Roman millstones from Orvieto (Italy): Petrographic and geochemical data for a new archaeometric contribution

The probable site of extraction and production of Pompeian -style leucite-b earing millstones, singled out by Peacock (1980, 1986) in the vicinity of O rvieto, and the outcropping of the 'Leucitophyre' lava have been systematic ally studied employing standard petrographic and geochemical methods (optic al microscopy and ICP-AES/MS spectrometry). The combination od petrochemica l data previously very poor, allowed us definitely to exclude the possible 'overlap' of phonolithic and tephi-phonolithic lavas from other Quaternary Volcanic Districts of Latium, provides a helpful tool for future work on le ucitite millstones. Consequently, the databank obtained has been used to at tribute the origin of five Roman millstones discovered in three archaeologi cal sites in central Italy (Latium and Marche). It has also been useful to verify the geological provenance of some Sicilian and French leucitite mill stones analyzed by previous workers. The results point to a provenance from the Orvieto area, with the exception of the millstones from Sicily, for wh ich a different origin was hypothesized.