XRF Analysis of Silver Coins Part from Coin Hoard from Sofia (CCCHBulg IX, Serdica III): Preliminary Report
Keywords:X-ray fluorescence (XRF) analysis, Portable spectrometer, Roman silver coins, hoard, Sofia 3/Serdica III
This preliminary report focuses on the results of a pXRF archaeometric analysis of 25 specimens of Roman silver coins from a coin hoard known as Serdica III (Sofia 3).
The analysis was performed by using a portable XRF spectrometer (X-ray fluorescence, S – Bruker Titan S1 Gold). The results reveal differing content of the following major elements: silver, copper, lead, and tin. The coins were minted in the period between the second half of the 1st century until the 3rd century AD.
X-ray fluorescence (XRF) analysis has become a standard method in numismatic and archaeological science due to its non-invasive and non-destructive nature. This technique has extensively been used for the study of numismatic collections since the data derived from it can be correlated with manufacturing processes, the provenance of raw materials, and the geographical distribution of ancient mints. The objective is to trace the amount of silver, as well as other elements in the alloy.
The analytical data obtained by the XRF method are statistically estimated. The preliminary evaluation of the coins indicated that the highest silver content varied as follows: the coins minted in the time of Vespasian, contained 94.2% while those for Trajan and Hadrian contained 90.3 % The lowest concentration was found in the coins of Julia Maesa (53.8 %), Severus Alexander (49.3 and 51 %) and Julia Mamaea – 53 %.