A Trial PIXE/PIGME analysis of Pre-Islamic Arabian Coinage

Eight previously published (1) pre-Islamic coins minted in Arabia were subjected to non-destructive ion beam analysis by Proton Induced X-Ray (PIXE) and Gamma-Ray Emission (PIGME) at Lucas Heights. The results (2) were interpreted using Principal Components Analysis (PCA). The relative X-ray intensities of fifteen elements, supplemented with additional L alpha lines for two of the elements, were extracted for this analysis. PCA (results appended) was first carried out on the whole dataset where the distinctive high iron and nickel composition of two coins (331 and 335) resulted in their position as outliers. A second analysis of the subset of silver coins showed the compositional similarity between four coins (44, 222, 226, 359) and distinguished two separate outliers. One of these (369) has a high lead and tin content while the other (354) has a greater proportion of elements present as impurities (?) including iron and nickel. The two outliers and the relatively homogenous compositions of the group of four coins suggest that three compositional types of silver coinage are represented in the dataset: 1. a relatively silver-rich group of four coins; 2. silver coins debased with lead; and 3. silver coins debased with iron and nickel.     

The Improved Lns Pixe‐Alpha Portable System: Archaeometric Applications*

The possibilities presented by the improved portable PIXE system are discussed. Examples are given of applications in the cultural heritage field, and in particular in the characterization of pigments and silver patina on ancient Roman coins. The limitations of the system are also discussed.     

NEUTRON ACTIVATION ANALYSIS OF ANCIENT BURMESE SILVER COINS WITH A LOW FLUX AMERICIUM/BERYLLIUM NEUTRON SOURCE

Nondestructive neutron activation analysis is by now a well-established technique for the analysis of ancient silver coins. The high activation cross-section of silver for thermal neutrons makes it possible to also use this method with the low neutron fluxes available from an isotopic neutron source. In this case due consideration must be given to minimize the self-shielding effect which is encountered with coins above a few tenths of a millimetre thickness. A simple method for the determination of the silver, copper and gold content in silver coins based on the self-shielding properties of silver alloys of different fineness is described. The method has been found to be useful for the quick routine assay of silver coins for the purpose of their classification. Seventeen ancient Burmese silver coins from three different cultural periods of Burma, and two British coins for comparison have been analyzed by this method.     

Chronological discrimination of silver coins based on inter‐elemental ratios using laser ablation inductively coupled plasma mass spectrometry (LA‐ICP‐MS)

This paper details the application of a statistical method for the chronological discrimination of silver coins using counts per second trace elemental, inter‐elemental ratios. The statistical method described is based on a method that has been applied to similar archaeological materials to determine their provenance. The method makes use of the inter‐element association patterns of multi‐element analytical data determined using laser ablation‐inductively coupled plasma‐mass spectrometry (LA‐ICP‐MS). The majority of the 266 coins analysed for this study have already been successfully identified by their mint markings. The data from LA‐ICP‐MS analyses, together with what is known about the coins through visual identification, were used to discriminate the reigning sovereign, and in the case of Mexico, the year of minting, of individual coins within the elemental fingerprint of different mints. Subsequently, unidentified coins can be placed in the confusion matrix, and their trace element information used to identify their year of minting when compared with other, identified coins from the same mint. The interpretational statistical technique linear discriminant analysis (LDA) was used to explore an identification of year of minting of coins that have previously not been identified by other means based on a statistical comparison against a database of compositional analysis of silver coins of known year of minting.     

Average and core silver content of ancient-debased coins via neutron diffraction and specific gravity

The measurement of the fineness of debased ancient silver coins has proven to be a very difficult issue, which has been studied for a long time. In this paper, this subject is analysed, and the various consequences of the silver surface enrichment (SSE) are discussed exploiting the most recent investigations. A new model is proposed for the complex object that is an ancient-debased silver coin, based on the silver profiles measured on some sectioned specimens. The model is applied to a sample of 43 coins, mainly Roman victoriati, Cisalpine and Illyrian drachms (from late III to I century B.C.). The coins are investigated in two different ways: neutron diffraction (ND) and specific gravity (SG). The results of the two measurements are combined via the proposed model to provide a more complete numismatic information of the original fineness of the monetary alloy. As a result, a relation between SSE thickness and SG is derived, which, for these coinages, allows to estimate the original alloy silver content from a simple SG measurement; the same method can be used to study other debased coinages, provided that all the procedure (ND and SG) is applied.     

AN ANALYSIS OF SOME THIRD-CENTURY ROMAN COINS FOR SURFACE SILVERING AND SILVER PERCENTAGE OF THEIR ALLOY CONTENT

The silver content within the body and at the surface of 22 Roman ‘bronze’coins dating to a.d. 274–305 was determined by X-ray fluorescence to discover whether these coins were silver dipped and/or issued with a deliberately added amount of silver in their alloy. Results of this analysis indicate that antoniniani and fractional coins of the period 274–294 were probably both silver dipped and minted in an argentiferous alloy. Radiate and laureate fractions issued after 295 do not seem to have had an argentiferous alloy, nor does this analysis provide any evidence that they were silverdipped.     

四川邛崃一批出土银元的分析与除锈保护

为了保护四川邛崃出土的一批银元,用SEM-EDS和XRD分析法对具有代表性的银元及锈蚀物成分进行了分析。结果显示,银元中除含主元素Ag之外,同时还含有一定量的Cu元素;表面锈蚀物大多数为铜的化合物——氧化亚铜和碱式碳酸铜,少量为角银。结合分析结果及试验,采用机械振动和5%EDTA二钠盐水溶液相结合的方法进行除锈,之后再缓蚀封护,并用有机玻璃制作的钱币专用盒封装存放。分析数据将为研究我国银元文物提供科学信息,保护方法将为银器类文物的保护提供应用实例。     

Metallurgical study on some Sasanian silver coins in Sistan Museum

Elemental analyses and microstructural studies of historical metal artifacts provide researchers with invaluable and priceless information about metal extraction technology and the procedure of creating artifacts. In addition, the information is helpful for knowing about the metallurgical processes of the artifacts. This study was conducted by a microscopic examination and elemental analyses of seven Sasanian silver coins preserved in the Sistan Anthropology Museum, Iran. For the purpose of this study, three methods were employed: first, the proton induced X-ray emission microanalysis (micro-PIXE), to determine the main and trace elements of the coins; second, scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS), to perform elemental analysis to identify impurities of the metal; and third, microstructural analysis of the coins which was carried out with an optical microscope (OM). The elemental analyses identified Ca, Cu, Ag, Au, and Pb in the coins. The high quantity of Ag in samples validated the application of advanced and accurate cupellation technology for refining silver and separating impurities from raw ore. The gold concentration in the coins indicated the use of non-galena ore for silver extraction. Additionally, the microstructural analyses of samples pointed to the application of thermo-mechanical processes on coins.     

Enhancing Understanding of the Emergence of Global Trade: Analysis of 17th‐ to 19th‐Century Spanish Coins Recovered from Western Australian Shipwrecks Using Laser Ablation – Inductively Coupled Plasma – Mass Spectrometry (LA–ICP–MS)

This research uses legacy data from shipwrecks to further our understanding of global silver movement in the 17th to 19th centuries by analysing a collection of silver coins held by the Western Australian Museum. Three hundred and eighty‐nine silver coins were analysed for their trace element fingerprint in order to identify provenance. The coins are a selection from the ships Batavia, Vergulde Draeck, Zuytdorp, Rapid and Correio da Azia, all wrecked off the coast of Western Australia between 1629 and 1816. Analysis was undertaken using laser ablation – inductively coupled plasma – mass spectrometry (LA–ICP–MS), a relatively non‐destructive technique with a sensitivity of parts per million to parts per billion. Data were interpreted using linear discriminant analysis (LDA), which allowed the coins of known provenance to be sorted into identifiable subgroups on the basis of their trace and minor elemental fingerprints, while 27 unidentified coins were compared with this database and their mint of origin predicted. These results have implications for the provenance determination of archaeological artefacts of many materials.     

A Study on the Xiwang Shanggong Coins Unearthed at the Jiangkou Site in Pengshan,Sichuan

An archaeological excavation was jointly conducted by organizations including the Sichuan Provincial Cultural Relics and Archaeology Research Institute in the first half of 2017 in the Jiangkou stretch of the Minjiang River in Pengshan District, Meizhou, Sichuan Province, where more than two hundred gold and silver xiwang shanggong coins were unearthed. This was the first time that the existence of xiwang shanggong coins was proved by a systematic archaeological excavation, providing a scientific basis for solving the long-standing unresolved historical problem. By sorting out the academic history of xiwang shanggong coins, this paper points out that in the past seven years, these coins have experienced the transition from being dug by robbers to being excavated scientifically, and have turned from a hot topic in collection to one in academia. This paper summarizes the characteristics of these gold and silver coins and presents an idea that those coins may have never been officially issued. Some of the coins have residual traces of being burnt, which may provide physical proof to prove the event in historical records that the fleet of Zhang Xianzhong was burnt by the army of Yang Zhan in the early Qing Dynasty. By using these unearthed xiwang shanggong coins as the standard and comparing them with some of the handed-down counterparts, this paper makes an in-depth analysis on the authenticity of the handed-down coins and indicates that some of the gold and silver ones may be authentic while some copper ones may be counterfeit.     

中国钱币博物馆部分陈列银币、铜币的腐蚀产物及成因研究

为探讨部分陈列银币、铜币腐蚀产物及其成因,采用三维视频显微镜、扫描电镜-能谱(SEM-EDS)、X射线荧光(XRF)、X射线衍射(XRD)等方法,对中国钱币博物馆部分遭受腐蚀的展陈钱币的腐蚀产物进行了分析,并通过红外光谱(FT-IR)对展陈材料进行了分析,最后对硫的来源进行了初步分析。结果表明,银币和铜币的腐蚀产物均含有硫化物,银币(银铤)的腐蚀产物为硫化银,铜币的腐蚀产物中主要为铜的硫化物,此外还含有铜的氧化物。经分析,展柜中的黏合剂氯丁胶在光照和较高温湿度条件下能分解并释放出硫化氢气体,因而初步判断银币或铜币的腐蚀产物是由于展柜内材料产生的硫化氢与银币或铜币反应生成。     

NON-DESTRUCTIVE RADIOISOTOPE X-RAY FLUORESCENCE ANALYSIS OF OLD SILVER COINS

The paper presents the results of a feasibility study of the application of X-ray fluorescence analysis to nondestructive analysis of coins. Radioisotope sources ⁵⁵Fe, ²⁴¹Am, ¹⁰⁹Cd and ²³⁸Pu were used for excitation and a Si/Li detector with a multichannel analyser for the measurement of characteristic X-ray lines. Silver and copper in Polish renaissance coins have been analysed. Analysis using Ag K and Ag L lines allows one to distinguish between blanched and unblanched coins. The accuracy of the silver determination using Ag K X-rays is claimed to be ± 0.5% Ag for homogenous coins and ± 1.0% Ag for blanched but well-preserved uncorroded coins.     

庚子之后制钱铸造体系的规复与解体

制钱铸造在庚子之变中遭受重创,此后经历了一个艰难规复、地方实践、观念转型、民间转向与最终解体的复杂过程。面对庚子后的钱荒危机,清政府通过批准开铸铜元、重建中央铸钱局、改铸新制钱、推广粤式制钱等钱法改革,于光绪三十三年初步规复传统的制钱铸造体系。但随着各省对铜元余利的倚重与货币本位制改革的推进,朝野人士对主、辅币关系形成新的认识,铜元超越制钱被纳入主辅币方案,一文铜元亦在光绪三十四年逆转一文制钱成为推行全国的一文新钱。由此,钱法改革从属于本位制改革,政府币制改革观念亦由银钱并行、分层开展转型为统筹划一、建立银本位,故制钱被排除在新币制之外,长期亏赔的宝泉局最后亦被撤销。同时,民间私钱历经泛滥与衰落之后,在宣统朝转入消亡期。至宣统三年,虽然官私制钱仍在广泛流通,但相关铸造活动已全面停止,这标志着自秦代以后运行两千余年的传统铸钱体系最终解体。     

The coinage of ancient Hadramawt The Pre-Islamic coins in the al-Mukallâ Museum

The pre-Islamic coins in the al-Mukallâ Museum come principally from Shabwa, the capital of the kingdom of Hadramawt. The collection consists of 76 coins, three of which could not be identified because of their poor condition. Sixty-seven silver and bronze Hadrami coins; five silver and bronze Himyarite and Sabaean coins; and one gold Roman coin comprise the collection. This material provides a general overview of the coinage of the ancient Hadramawt, permitting us to distinguish the issues of certain individual Hadrami rulers.     

ROME AND THE EAST. PRODUCTION OF ROMAN PROVINCIAL SILVER COINAGE FOR CAESAREA IN CAPPADOCIA UNDER VESPASIAN, AD 69–79

During the first three centuries AD several eastern provinces of the Roman empire produced silver coinages of specifically local denominations and types. It has been claimed that at certain periods the mint of Rome was employed to strike some of these coinages, rather than the provincial mints to which the coins are traditionally attributed. This claim is based mainly on stylistic observations, but because style is regarded as subjective, some other form of evidence to support these observations is desirable. In this paper three types of coin are submitted to metallurgical analysis: silver denarii struck at Rome; Roman-style provincial silver coinage; and 'local'style provincial silver coinage. The aim is to discover whether the Rome-style and 'local'style coins have different trace element profiles, and whether these might indicate different ore sources or refining techniques. The results are then compared with Roman denarii to see whether there are any similarities between the denarii and the Rome-style provincial silver coins.     

DETECTION OF NEAR-SURFACE SILVER ENRICHMENT ON ROMAN IMPERIAL SILVER COINS BY X-RAY SPECTRAL ANALYSIS*

A collection of 218 Roman imperial silver coins, covering three centuries, was analysed non-destructively by two variants of X-ray spectral analysis. Electron beam excitation and energy-dispersive spectrometry was used for the analysis of the uppermost thin layer (3 μm) of each coin, while X-ray tube excitation and wavelength-dispersive spectrometry was applied for the analysis of thicker layers (30 μm), Ag and Cu as major constituents and 18 minor elements were determined quantitatively. Comparing the silver content of the obverse and the reverse of a coin, inhomogeneities could be identified. By comparison of the silver content of the upper thin and the thick surface layers, near-surface silver enrichment could be detected. Inhomogeneities and enrichments increase in the second and more so in the third century. A large scatter of the silver content and silver enrichment for coins of the same emperor was attributed to varying abrasion of Ag-enriched layers of the individual coins during decades of circulation.     

THE USE OF SPECIFIC HEAT IN THE NON-DESTRUCTIVE ANALYSIS OF SILVER/COPPER ALLOY COINS

Using partly plastic apparatus, specific heats of coins have been found calorimetricly to an accuracy of ± 3% for most coins. For silver/copper alloys the specific heat varies approximately linearly with the weight percentage composition, so the latter can be calculated for coins of unknown composition.     

X-RAY FLUORESCENCE AND DENSITY MEASUREMENTS ON SURFACE-TREATED ROMAN SILVER COINS*

Some 630 Roman silver coins excavated at Augusta Raurica (Switzerland) have been analysed by non-destructive X-ray fluorescence and X-ray diffraction. Furthermore, the density and the weight have been determined. The measured average density of plated and massive depletion-silvered coins is lower than the density calculated from the chemical composition, whereas massive coins display equal values for both of the densities. Based on experimental X-ray investigations of modern silver (tempering, acid treatment, production of corrosion layers), the nature of corrosion products on silver, their impact on surface analysis, and aspects of wearing-off by circulation are briefly discussed.     

New insights into the ancient silver production of the Wallis area, Switzerland

This paper discusses the results of a study of the exploitation history of the metallogenic region of the Wallis, Switzerland. Periods of exploitation in this mining district are determined by comparisons of the lead isotope fingerprint of the mines with those of dated artefacts presumed to have a local origin based on the style of craftsmanship. The approach is based on the study of silver mines in the Wallis area and illustrated by three examples of local craftsmanship: (1) silver jewellery from the Late Iron Age, (2) a reliquary shrine from the Early Middle Ages and (3) silver coins from the Late Middle Age.     

QUANTITATIVE ANALYSIS OF COPPER-TIN BRONZES BY MEANS OF GLOW DISCHARGE OPTICAL EMISSION SPECTROMETRY

Glow discharge optical emission spectrometry (GDOES) has been used for obtaining calibration curves for copper, tin, lead, silver, antimony, arsenic, zinc and iron from standards including copper-base alloys (Cu 61.33-99.95%) and from bronze Punic coins. The GDOES results were calibrated using atomic absorption spectroscopy with inductively coupled plasma atomization (ICPAAS) to analyse the standards and coins. For all these materials, the results show that via GDOES it is possible to obtain reliable and reproducible calibration curves for copper, tin, lead, zinc and iron with a linear behaviour as a function of the content. The quantitative GDOES and ICPAAS data for the coins have been also compared with those obtained via X-ray fluorescence (XRF) and it is shown that GDOES, ICPAAS and XRF agree well with one another considering that the bronze coins are inhomogeneous to some degree. As an example of GDOES analytical features, a depth concentration profile through a thin bronze patina is shown and briefly discussed.