X-Ray Fluorescence Analysis and Self-Organizing Maps Classification of the Etruscan Gold Coin Collection at the Monetiere of Florence

The "Monetiere" of Florence hosts the most important collection of Etruscan coins in the world. In the framework of the longstanding collaboration between the Monetiere and the Applied Laser and Spectroscopy Laboratory in Pisa, the Etruscan gold coin collection of the museum was studied. The measurements were performed at the Monetiere, using a portable energy-dispersive X-ray fluorescence (XRF) instrument. The quantitative determination of the gold alloys used for the realization of the coins was obtained applying the fundamental parameters method to the XRF spectra; as a result, using the self-organizing maps method, we were able to classify the coins in four main groups. The main parameter determining the classification is the quantity of silver in the alloy. The results obtained shed some light about the origin of the coins under study.