A survey on the deterioration processes of the Renaissance monument to Giovanni Calfurnio in the St. Anthony's Basilica in Padova, Italy

In order to plan urgent restoration work, a series of minero-petrographic and chemical analyses was carried out on stone materials and decay products of a Renaissance funerary monument made of "Pietra di Nanto" (Nanto stone), now located in the Novitiates’ Cloister of St. Anthony’s Basilica in Padova (NE Italy). Macroscopic examination indicated deterioration forms such as exfoliation, disgregation, efflorescence and black scabs, widespread on the deep bas-relief of the monument. The diagnostic phase revealed deterioration patterns in the artwork and also the influence of atmospheric pollutants and the texture/structure of the stone on decay processes. Decay was mainly associated with the presence of gypsum (CaSO42H2O) and salnitre (KNO3). Traces of pigments were found and analysed, in order to reconstruct the original appearance of the monument.