Analyses of Roman silver coins.doc (original) (raw)
Molecules
In this study, 160 silver-copper alloy denarii and antoniniani from the 3rd century A.D. were studied to obtain their overall chemical composition. The approach used for their characterisation is based on a combination of physical, chemical, and chemometric techniques. The aim is to identify and quantify major and trace elements in Roman silver-copper coins in order to assess changes in composition and to confirm the devaluation of the currency. After a first cataloguing step, μ-EDXRF and SEM-EDX techniques were performed to identify the elements on the coins’ surface. A micro-destructive sampling method was employed on a representative sample of the coins to quantify the elements present in the bulk. The powder obtained from drilling 12 coins (keeping the two categories of coins separate) was dissolved in an acidic medium; heated and sonicated to facilitate dissolution; and then analysed by ICP-AES and ICP-MS. The two currencies had different average alloy percentages; in particula...
Internet archaeology, 2023
Wood et al. (2023), hereinafter WPB, unveils a number of historical issues relevant to Roman economy and metallurgy based on trace element and Pb isotope abundance data on a large set of important coins minted during the Roman Empire (Ponting and Butcher 2015). Here, we discuss several points which, in our view, misrepresent the work of other groups, ours included, and bias the overall interpretation of the WPB data set.
Mints not Mines: a macroscale investigation of Roman silver coinage
Internet Archaeology, 2023
Although silver coins have been investigated through the lens of geological provenance to locate argentiferous ore deposits exploited in their production, we consider that this avenue of research may be a cul-de-sac, especially for studies that rely heavily on deciphering lead and silver isotope signatures that may have been altered by the addition of lead and copper (and their associated impurities) during silver refining and debasement, and by ancient recycling of coinage. Instead, we focus our attention on mints, by analysing the compositions of over 1000 silver coins from the early 1st century BC to AD 100. We propose that lead from the west Mediterranean was used exclusively to refine silver at mints in the West, and that an unknown lead supply (possibly from Macedonia), used in the East by the Late Seleucid ruler Philip I Philadelphus and later Mark Antony, was mixed with western lead. Extensive mixing of lead and/or silver coins is particularly evident under Nero and Vespasian, aligning with historically attested periods of recycling following currency reform. We further propose that coins minted in the kingdom of Mauretania used different lead and silver sources from the majority of coins minted in the western Mediterranean, and that silver coins minted at Tyre are derived from silver refined in the west Mediterranean. Coinage minted at Alexandria is consistent with debasement of recycled Roman denarii, thereby suggesting that denarii were deliberately removed from circulation to mint tetradrachms during the early Imperial Roman period.
Complex archaeometallurgical investigation of silver coins from the XVI th -XVIII th century
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2017
When dealing with cultural heritage artifacts, the use of non-invasive and non-destructive analyses techniques is a must. Determination of the surface corrosion layers and coin composition is important both for identifying compounds that form different alloys (which can be considered support material for important objects, such as numismatic artifacts), and also for their conservation. The selection of analytical techniques is of great importance, as it is a strict condition that the structure of the artifacts should not be affected. The paper presents the archaeometallurgical study of seven silver coins, using several nuclear techniques (X-ray fluorescence-XRF, X-ray diffraction-XRD, Particle induced X-ray emission-PIXE) and optical microscopy. The study was performed using bulk methods and micro-area measurements in order to establish their composition, as well as the presence of corrosion products. This could, in turn, provide information in support of the categorization in genuine/possible forgery. From the analyzed set of samples, six can be surely categorized as genuine, while one raises some questions. A decisive conclusion cannot be drawn for one of the analyzed samples, but the scientific evidences suggest either a misstruck or a forgery approximately contemporary with the original issue of these coins.
Further metallurgical analyses on silver coins of Trajan (AD 98–117)
Journal of Analytical Atomic Spectrometry, 2011
Within an interdisciplinary project, preliminary results of which were published in 2007, a group of 65 silver coins (denarii) of Trajan, evenly distributed over the entire span of his reign (2nd to 6th consulate), as well as 3 coins from the reign of his predecessor, the emperor Nerva (AD 96-98), had been acquired on the coin market. These pieces could be cross-sectioned in order to carry out analyses. Measurements were performed with m-XRF and m-SRXRF to check the fineness of the denarius alloy as well as to investigate if the coins of the different consulates showed distinct traits concerning the main impurities which could suggest a change of ore sources. Furthermore, it was examined whether the influx of precious metals into the Roman treasury after Trajan's Dacian campaigns (AD 101/102 and 105/106) could have had any repercussions on the composition of the denarius alloy; comparative data was provided by the analysis of nine imitations of Roman Republican denarii presumably struck in Dacia. Documentation of the cross-sections was performed with SEM/EDX in order to clarify details concerning the specific microstructure of the coins. An enrichment of Ag of approx. 100 to 200 mm in the near surface regions of most of the coins could be observed, which is due to corrosion effects. Previous metallographic analyses done by several scholars had been inadequate to clarify the central numismatic and economic questions. With the presented analyses, it was possible to correct the results of the earlier research and to provide, for the first time, a secure basis of data for the investigation of the development of the silver alloy used for denarii in Trajan's reign.
Journal of Archaeology, 2014
This work enters in an interdisciplinary research project involving the archaeometrical analysis of ancient silver coins minted in the Greek colony of Taras (the modern south Italian town of Taranto) between the V century BC and the III century BC. In this work, by comparing the results obtained from X-ray microanalysis data acquired from the least corroded surface areas and the cross-section of coins from SEM-EDX and from XRF analysis, we have demonstrated that analysed coins exhibited a corrosion layer no more than 25 μm and that surface silver enrichment was less than 1 wt%. Thus, the data obtained by using X-ray microanalysis from surface may not significantly differ from the original bulk composition. Our results demonstrate that the silver content in the coins decreases considerably ranging from about 97% for the older down to 80% for the ones of 3rd Evans period (300–270 BC), corresponding to the significant social change in the period.
WHY WE ANALYZE THE ELEMENTAL COMPOSITION AND WEIGHT OF ANCIENT SILVER COINS
Acta Archaeologica Lodziensia, 2022
[Rewiev] Kevin Butcher and Matthew Ponting, with contributions by Jane Evans, Vanessa Pashley and Christopher Somerfield, The Metallurgy of Roman Silver Coinage: From the Reform of Nero to the Reform of Trajan, First paperback edition, Cambridge University Press, 2020, pp. XXXII + 797.