Non destructive investigation on Greek and Roman jewelry collection at the Paolo Orsi Regional Museum in Siracusa using mobile Raman equipment

In recent years, the use of mobile Raman equipments archeological, artistic and conservation tool has largely increased due to the possibility to obtain quick and non-destructive compositional analysis on unvaluable, unmovable, unique art objects [1]. In particular, art and archaeological museums can take big advantage in performing in-situ measurements in a short time and without moving them. In this work, we report on the campaign of Raman measurements carried out on the important collection of Greek and Roman jewels preserved in the Paolo Orsi Regional Museum in Siracusa (Sicily, Italy) with the aim at confirming the compositional attribution of the gems and gemological materials present in the collection. Measurements were carried out using two different instruments: an handheld spectrometer DeltaNu RockHound operating at 785 nm and a portable spectrometer Enwave EZRAMAN-I-DUAL equipped with two laser sources at 785 nm and 532 nm. Sixty jewels dated back to Hellenistic period, namely loose gems, earrings, rings, necklaces, pendants and various artifacts [2-4] have been analysed. In all cases the composition of the gems was identified. For many jewels the composition was found coherent with the archeological attribution, while in many cases the obtained results reveal the use of natural and artificial simulants; in some case we found important differences, sometimes surprising. In conclusion, by means of mobile Raman instrumentations it has been possible, in just a day of measurements, to check and, in some case, re-define the composition of some important archaeological jewels, without any damage or stress for the precious items. [1] P. Vandenabeele, Journal of Raman Spectroscopy 35(8-9), 2004, 607-609 [2] A. Crispino, scheda in F.Caruso-G. Monterosso ( a cura di), Dioniso Mito immagine teatro, catalogo della mostra, 30 settembre 2012, Siracusa 2012, p.80 [3] P. Orsi, Sepolcro con oreficerie in contrada Dammusi, in Notizie degli Scavi 1915 , pp. 87-88, fig. 7 (disegno di R. Carta) [4] L. Bernabò Brea, scheda in P. Pelagatti-G. Voza (a cura di), in Archeologia della Sicilia sud-orientale, Napoli 1973, p.7