Analysis of the Hoard of Beçin using X‐ray‐based techniques

Abstract

Four hundred and sixteen silver coins stemming from the Ottoman Empire (16th and 17th centuries) were analyzed to confirm the fineness of the coinage as well as to study the provenance of the alloy used for the coins. As most of the coins showed the typical green patina on their surfaces due to corrosion processes that have led to the depletion of copper in the near surface domains of the silver coins in comparison to their core composition, small samples had to be taken, embedded in synthetic resin, and cross sectioned to investigate the true‐heart metal composition. μ‐synchrotron micro X‐ray fluorescence analysis and μ‐proton‐induced X‐ray emission were applied to determine the silver contents as well as the minor and trace elements. The type of the alloy was investigated as well as if coins minted in different locations demonstrated homogeneous traits concerning the predominant impurities (Au and Bi), which could suggest a common ore. Finally, energy‐dispersive microanalysis in a scanning electron microscope was applied to study the homogeneity/heterogeneity of the coins and the presence of surface enrichments and to explain differences between the μ‐synchrotron micro X‐ray fluorescence analysis and μ‐proton‐induced X‐ray emission measurements concerning the main component. In general, the silver content of the analyzed specimen varies between 90 and 95%. These outcomes have not supported the historical interpretations, which predict that during the period studied, a debasement of approximately 44% of the silver content of the coins should have occurred. Copyright © 2012 John Wiley & Sons, Ltd.

Atomic spectrometry update: review of advances in the analysis of metals, chemicals and materials

“…There was a remarkable connection between the quality of the silver and some crucial contemporary events. A group of 416 silver coins from the Ottoman Empire (16th and 17th centuries) were analysed to Rodrigues et al 47 to conrm the neness of silver and also to study the provenance of the alloys used in the manufacture of these coins. Small cross sections of the coins were cut, embedded in plastic and analysed using SR-mXRF and mPIXE.…”

A Review of Energy Dispersive X-Ray Fluorescence (EDXRF) as an Analytical Tool in Numismatic Studies

“…Therefore, this technique can be of great support in historical studies. 4 An analysis of Indian silver coins used during British rule was carried out by Tripathy et al 32 The EDXRF instrument employed incorporates a low power air-cooled, Tungsten anode X-ray tube, as an excitation source with triaxial geometry. The X-rays from the tube, which was operated at 25 kV with 0.6 mA current, fell on a Mo secondary exciter, and a Si(Li) detector, cooled with liquid nitrogen, with a resolution of 170 eV at 5.9 keV, was employed.…”

“…3 At the same time, archaeological and historical objects such as coins are valuable artifacts, often unique and irreplaceable, and they must be analyzed using techniques that cause minimal damage to the sample. 4 In this sense, the development of non-destructive analytical techniques has helped to achieve this objective, and, among them, X-ray emission techniques have been extensively used in numerous analytical investigations. 5 X-rays are a short wavelength form of electromagnetic radiation placed in the region between gamma rays and ultraviolet radiation.…”