THE ACCURACY OF THE SPECIFIC GRAVITY METHOD FOR THE ANALYSIS OF GOLD ALLOYS

Two possible sources of error in the measurement and interpretation of the specific gravities of gold coins are investigated. First, the effect of the presence of copper was measured and found to be more significant than previously thought. It is shown that the presence of 5% of copper in a gold-silver alloy results in a measured gold content which is 3.3% too low when the coin is analysed by the specific gravity method. Secondly, the importance of cleaning the coins before measuring the specific gravity is also demonstrated.     

A STUDY OF THE SILVERING PROCESS OF THE GALLO‐ROMAN COINS FORGED DURING THE THIRD CENTURY AD*

We have observed by fast neutron activation analysis (FNAA) that the global composition of the official silver coins of the Gallic emperor Postumus is not the same as those from the contemporary unofficial mints. In order to explain this phenomenon, we have carried out a metallographic study of the artefacts. Then, we have re‐created the silvering process of unofficial coins in order to better understand the manufacturing process of silvering. The different steps of the replication process are explained in this paper.     

THE ANALYSIS OF GOLD COINS—A COMPARISON OF RESULTS OBTAINED BY NON-DESTRUCTIVE METHODS

This paper discusses a systematic difference between the results found when one series of Dark-Age gold coins were analysed both by neutron activation and by specific gravity analysis and when a second series of similar coins was analysed by the Oxford Milliprobe and by specific gravity. No reason is given for this systematic difference, although there is evidence that all three methods are slightly in error, two of them giving results for gold which are too high and the specific gravity method giving results which are too low.     

THE COMPOSITION OF IRON AGE STRUCK 'BRONZE'COINAGE IN EASTERN ENGLAND

EDXRF was used to analyse the composition of 88 Iron Age copper and copper alloy coins excavated from the site of a pre-Roman shrine and Roman temple at Harlow, Essex. Most of the coins are local to the Essex-Hertfordshire region, with a few of Kentish origin. The earliest struck base metal issues were struck from almost pure copper, but from the late first century BC, their composition shows more variety. Particularly interesting are a group of types belonging to the Romanizing phase of Tasciovanus'coinage, which were struck in brass and possibly represent a distinct denomination. Roman coinage and other metalwork imports from the Roman world presumably provided the initial impetus, and the ultimate source of the brass. However, this experiment was relatively short lived. Cunobelinus, who ruled eastern England during the earlier first century AD, mainly employed bronze to strike his abundant base metal coinage. The products of his Colchester mint reveal a consistently different composition from those struck at his unlocated second mint in the Hertfordshire area, although the precise alloy does vary, sometimes within the same type. This suggests that unlike gold and silver issues, the source and purity of the metal used for minting base metal coinage was not always critical.     

THE BADBURY-SHAPWICK HOARD AND THE DATE OF THE MAIDEN CASTLE COINS FROM SIR MORTIMER WHEELER'S 1934–1937 EXCAVATIONS

Summary. Fifteen Celtic coins found during Sir Mortimer Wheeler's excavations have never been dated with precision. A hoard of similar coins, found in the vicinity of Badbury Rings hillfort gives us a yardstick for their chronology.     

THE REMANENT MAGNETIZATION OF ANCIENT STRUCK COINS

Magnetic and other measurements are reported for the Guehenno II Gallo-Roman hoard (56-France) which, amongst several thousand Tetricus antoniniani, contains 275 coins struck with the same dies. The orientation of the remanent magnetization is systematically directed outwards from the obverse confirming the identity of the anvil die with the obverse. The magnetization vector is statistically distributed around the vertical axis giving no indication of the geomagnetic inclination at the time of striking. Consequently ancient struck coins cannot be used for dating. The origin of the remanent magnetization was also investigated.     

THE CHRONOLOGY OF GROUPS OF DIES FOR LARGE ISSUES OF ANCIENT COINS USING MAHALANOBIS DISTANCES*

Discriminant analyses of distances and angles obtained from 25 coins struck by P. Crepusius in 82 BC permitted the correct chronology for five groups of closely-related dies to be obtained by the method of Carter and Frurip. Twenty distances and 15 angles were measured on 10 x projections of the coins which represented five groups of dies separated in time from each other. The use of all or many variables gave poorer results than the use of five to ten variables having a high ‘figure of merit’, defined as the maximum range of mean values for a given variable in the five groups of dies divided by the mean standard deviation of the variable in the five groups. It is recommended that chronologies of ancient coins be determined from Mahalanobis distances by using only variables of relatively high figure of merit.     

AN ANALYSIS OF THIRTY-ONE COINS FROM THE HELLENISTIC PERIOD

Thirty-one silver coins of the Hellenistic period were examined by the particle induced X-ray emission (PIXE) method, and the results incorporated into a wider study of the coins. Some tentative conclusions reached in the study are mentioned, together with an outline of the PIXE method. A number of patterns emerged in the results, the most important being an apparent deterioration in silver content among the later Seleucid and Ptolemaic issues; some high concentrations of particular elements were also noted.     

THE TREASURE OF GUARRAZAR: TRACING THE GOLD SUPPLIES IN THE VISIGOTHIC IBERIAN PENINSULA*

The treasure of Guarrazar, found in the 19th century in Spain, is the most important illustration of the high level of Visigothic jewellery in the Iberian Peninsula. The votive crowns and crosses of this treasure are an arrangement of pierced gold in a Byzantine–Germanic style, decorated with emeralds, garnets, sapphires and other materials. In order to establish the provenance of the gold, we analysed a group of 46 minute samples from the most important pieces kept in Spain for major and trace elements. The combination of PIXE and PIGE with an external 3 MeV proton µ‐beam was used to analyse the samples. Considering the gold sources cited by Pliny the Elder and the composition of contemporary Visigothic coins, we suggest the exploitation of south Iberian mines. Using the same set‐up, we complemented these results with the analysis of 11 emeralds inlaid in items from the Guarrazar jewellery that is kept in France. We suggest the use of European sources unknown to the Romans for these gemstones.     

云南香格里拉迪庆藏族自治州博物馆藏币的科学分析

为了解西藏钱币的制作工艺,采用金相显微镜组织观察和扫描电子显微镜分析的方法,对云南香格里拉迪庆藏族自治州博物馆收藏的五枚藏币样品进行分析。分析结果表明,五枚藏币可以分作两类,一类为铜质,一类为银铜合金。铜质钱币为含铜率高达99%,可以判定为纯铜制品;银铜合金币的配比基本符合"银八铜二"的合金化的要求。五枚钱币全部采用机械冲压制作,符合当时社会的生产动力变化。本研究成果对进一步研究西藏地区钱币的工艺技术有一定价值。     

我国古代黄铜铸钱考略

本文从既有的实物分析资料出发,广泛地结合历史文献,对我国古代用黄铜铸钱的历史作了详细的考证,指出:我国古代自明嘉靖三十二年始用黄铜铸钱;早期用黄铜铸钱在铸造上是无意识的,黄铜由红铜与含锌矿(炉甘石)合炼而来;自明天启年起,金属锌以单质形态用于铸钱。 从现有的材料看,汉代已有含锌百分之七的铜钱,据称,宋绍圣钱中个别的含锌量达百分之十三。然而,尽管如此,从汉唐至宋元,含锌量超过百分之一的钱仍属极少数(据笔者统计,已分析的1000余枚铜钱中,含锌量达百分之一的只有40余枚,达百分之十以上的仅有一枚),有关文献记载中也不见有用黄铜铸钱的迹象;另一方面,从组成成分来看,这些含锌量较高的铜钱中,锌的含量大都还低于铅锡之含量。因此,都还不能说是用黄铜铸钱。其中的锌,或者随原料铅夹杂而来,或者是偶然引入输石器之故。文献和实物分析的结果表明,我国真正用黄铜铸钱始于明朝。     

ARCHAEOMETALLURGICAL CHARACTERIZATION OF HELLENISTIC METAL OBJECTS: THE CONTRIBUTION OF THE BRONZE OBJECTS FROM RISHON LE‐ZION (ISRAEL)*

An archaeometallurgical analysis is presented of 14 bronze artefacts retrieved from an Early Hellenistic–period farmstead in controlled archaeological excavations at Rishon Le‐Zion, Israel, and dated to the first quarter of the third century bce according to coins and pottery vessels. The bronze assemblage includes a needle, pins, spatulas and fibulas. The aims of the research are to determine the composition, microstructure and manufacturing process of these artefacts, and to discover their place of production. This will provide a better understanding of Hellenistic technological abilities and material culture. The examination included optical microscopy, microhardness, SEM including EDS, and XRD. The results show that the collection consists of Cu–Sn binary alloys, with evidence for a controlled alloying process and the absence of recycling. Furthermore, the microstructure of the objects indicates that all artefacts were produced by a cold‐working process. Moreover, the manufacturing process of the rectangular cross‐section fibulas included sophisticated joining techniques of copper and iron.     

The Evolution of Pre‐Islamic South Arabian Coinage: A Metallurgical Analysis of Coins Excavated In Sumhuram (Khor‐Rori,Sultanate of Oman)

The present paper deals with compositional and microstructural features of 26 pre‐Islamic, South Arabian coins recently unearthed during archaeological excavations. Most of the investigated coins come from Sumhuram (Khor Rori, southern Oman), and were minted by the Hadramawt kingdom (fourth century bc to third century ad ); only a few of them belong to the Himyarite kingdom's coinage (first to fourth centuries ad ). In addition, some coins of both the Hadramawt and the Himyarite kingdoms found at Qani' (B'ir ‘Ali, Republic of Yemen) have been analysed for comparison. Our main focus was to provide new hints towards the comprehension of the chronological evolution in South Arabian coinage in terms of both metal composition and minting techniques. In addition, some melting crucibles found at Sumhuram have been examined in an attempt to make a comparison with the coins’ composition and to test the hypothesis that they were used for minting operations.     

A SIMPLE INSTRUMENT FOR MEASURING THE DENSITY OF SOLID OBJECTS

A simple and easily constructed instrument is described for the direct measurement of the volume of solid objects, such as coins, to a high accuracy. The density of the object is readily calculated by dividing the weight of the object by its volume.     

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.     

四川地区西汉土坑墓分期研究

目次一墓葬形制分析二随葬器物类型学研究三墓葬分期与变迁分析四墓葬区域特征分析五结语四川地区(包括今重庆市)西汉时期的墓葬,以土坑墓为主。该地区20世纪90年代以前发现的西汉时期墓葬虽然数量相对较多,但大部分材料较零散,且多数墓葬中的器物保存较差,资料不够完整。正是由于上述原因,迄今未有专文对四川地区西汉土坑墓进行研究,仅有个别文章有所涉及,始终无法深入。何志国对四川地区西汉土坑木椁墓进行了初步分析后,做了大     

THE USE OF ROMAN COINAGE

Summary. There is little doubt that Roman coins found today in excavations were lost during the Roman period because they were in use. If these coin-finds are examined in the appropriate way it should be possible to detect something of the patterns of coin-use and coin-loss in the ancient world and hence to learn something of the monetary side of trade and the economy. Finds from different sites are compared in an effort to establish basic rules of interpretation, or, failing that, of presentation of the evidence.     

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.     

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.     

APPLICATION OF MUONIC X-RAYS IN ARCHAEOLOGY

The first systematic study of archaeological objects with muonic X-rays is reported. In this analysis every element is recognized. The elemental composition of Celtic glasses from Bavaria and Roman coins has been determined. By selecting the primary muon energies appropriately my part of the specimen, including interior parts, can be non-destructively in estigated. Additionally surface layers may be analysed. Typical accuracies of quantitative analyses are a few per cent of elemental abundance.