Petrographic study of pietra ollare mills from Garda Civic Museum in Ivrea (To)

Abstract

An archaeometric study of Roman age pietra ollare mills preserved at Pier Alessandro Garda Civic Museum of Ivrea (Piemonte, NW Italy) was performed, to enhance the historical stone employed in the ancient Eporedia (current Ivrea) and to make more available the archaeological heritage of this city. The petrographic analysis and the study of their mineral composition with the electronic microprobe allowed to attribute a local provenance to the millstones studied. In particular, two millstones resuted garnet chloritoschists, that showed petrographic characteristics similar to pietra ollare of Aosta Valley, while a third millstone consisting of a jadeite micaschist probably comes from the high pressure rocks of the Eclogitic Micaschist Complex of the Sesia-Lanzo Zone.The analyses of these materials is part of diagnostic-conservative and fruition project of the municipality of Ivrea, in collaboration with Soprintendenza Archeologia, belle arti e paesaggio per la Città metropolitana di Torino, the Municipality of Ivrea and the Fondazione Guelpa.