Micro X-ray fluorescence analysis of Roman Imperial coins from Nero

A group of 364 Roman Imperial coins, issued by Nero (37-68 A.D.) and exhibited at the National Archaeological Museum of Florence, was non-invasively investigated by micro X-ray fluorescence analysis. The research aimed at correlating the events of Nero's monetary policy, mainly the reform of 64 A.D., with possible variations in the weight and composition of coinage. We observed that the reform produced: a) weight reduction and/or debasement for both precious metal and orichalcum coinage and b) higher disorder in the coinage production of 64 A.D. and the immediately subsequent years. Thanks to the capability of performing measurements on the small patina-free areas already present on the coin, with no need for abrasion, micro X-ray fluorescence proves an effective option for the non-invasive analysis of ancient coinage.