The silver collection of San Gennaro treasure (Neaples): A multivariate statistic approach applied to X-ray fluorescence data

In this work we report an X-ray fluorescence spectroscopy (XRF) study combined with a multivariate approach allowing to detect compositional differences and similarities among the alloys used in realization of silver collection of San Gennaro items collection. The San Gennaro treasure in Naples (Italy) represents, in fact, one of the most important silver collections in the world. The classification of the collection items is very complex, not only for the large number of objects, but also in consideration that between 1600 and 1700, in Naples, more than 350 laboratories were active, most of them specialized in specific art of work. As a consequence, a given collection object could be composed by various silver pieces that were produced by different laboratories. We applied a multivariate analysis on the XRF measurements data set to find a classification criterion based on the alloy elemental composition. Results showed that the collection items, as a whole or parts of it, can be divided into four large groups characterized by their different Ag/Cu ratio.