Analyses of Roman silver coins.doc (original) (raw)
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Analysis of ancient silver coins
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2004
Writing from the numismatist point of view, the authors open this paper by reviewing critically the use of scientific methods for the studies of ancient coins. They also report about an application of the PIXE method at low incident proton energy to one of the most celebrated and known coinage in the ancient history: the Athenian silver coins of the fifth century BC. The results of those analyses indicate that the metallic composition of several coins usually taken as ancient imitations of Athenian coins does not differ from that of the genuine ones. Those analyses confirm what the authors have inferred from numismatic sources: These coins are probably genuinely Athenian.
Analysis of 16 th to 19 th Century Silver Coins
This thesis demonstrates the application of a number of analytical techniques on a selection of silver coins from the Western Australian Museum. Results of analysis are used to appraise the applicability of surface analytical techniques on samples that have corroded. Analysis has also been used to determine when, where and how coins too heavily corroded to visually identify were minted. Further, the importance of maintaining large collections and assemblages of objects in museum collections is demonstrated, and further applications of the techniques used are discussed. Four hundred silver coins and a selection of silver artefacts were provided for analysis from the collection of the Western Australian Museum. The coins and artefacts were recovered from the following shipwrecks; the Batavia wrecked 1629; the Vergulde Draeck, wrecked 1656; the Zuytdorp, wrecked 1712; the Rapid, wrecked 1811; and the Correio da Azia, wrecked 1816. All of the ships were wrecked off the coast of Western Australia. The coins represent 22 mints in Spain, Spanish America, the United Netherlands, Germany, and the Spanish Netherlands, and 19 European sovereign issuers from Spain, Saxony, the Holy Roman Empire, Denmark and Norway, the United Netherlands, Holstein Gottorp, and Saxe-Coburg Saxe-Eisenach. The coins were minted between 1560 and 1816. Samples were analysed using non-destructive analytical techniques: inductively coupled plasma mass spectrometry (ICP-MS) and scanning electron microscopy (SEM). These semi-destructive techniques were chosen in order to demonstrate their effectiveness in gleaning further information from items of cultural heritage significance, than is possible through a visual analysis alone. Silver coins and artefacts were chosen for analysis due to the large assemblage of silver coins held by the Western Australian Museum, making it possible to create a database of analytical results from coins of both known and unknown mint of origin and year of minting for the sake of effective comparison. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), a technique which facilitates multi-element analysis without causing significant damage to the coins themselves. Thirty-eight elements were determined in triplicate for each coin thereby providing individual elemental “fingerprints”. Data were interpreted using linear discriminant analysis (LDA) which allows the coins to be grouped into easily identifiable sub-groups. Using LA-ICP-MS plus LDA it was possible to use the trace and minor element composition of the coins to identify chemical signatures which are specific to the mints of origin. This information was then cross-referenced against the trace and minor elemental composition of damaged and unidentifiable coins to determine their mint of origin and year or decade of minting. A selection of samples was also analysed using scanning electron microscopy (SEM), a technique which facilitates further understanding of the manufacturing history of the samples based on backscattered electron (BSE) images and electron backscatter diffraction (EBSD) structural maps. Diffracted backscattered electron images can be used to assess the crystallographic structure of the sample and to assess areas of possible inhomogeneity, both of which are indicative of techniques used to manufacture objects of silver and silver alloys. This analysis complements LA-ICP-MS analysis by providing the manufacturing history of the samples, on top of the identification of their provenance and year of manufacture. This research gives new information about economic networks, including trade between the Americas, Europe and the Far East during the 16th, 17th and 18th centuries, the height of the great maritime empires, and more specifically, the procurement, manufacture and trade of silver as a global commodity at this time. Further, the techniques used in this study are applicable to many other items of cultural heritage significance for future analysis.
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.