LA CHRYSOCOLLE DES ORFEVRES EST-ELLE JAUNE?

During the investigation of solders on ancient gold artifacts found in Iran and Syria, cadmium was found at a concentration up to several per cent. Careful interpretation of relative concentrations of copper, silver and cadmium in those solders easily enables discrimination between brazing of modern and ancient origin and forms a simple criterion of identification. Experimental archaeology corroborates this. We suggest a new interpretation of Book XXXIII of Pliny the Elder on the soldering of gold: the chrysocolla of the goldsmith, gold solder, could be greenockite (natural cadmium sulphide) and not necessarily malachite (natural copper carbonate).     

Never Judge A Gold Object by Its Surface Analysis: A Study of Surface Phenomena in a Selection of Gold Objects From the Staffordshire Hoard

With the introduction of commercially available handheld XRF analysers, there is a growing problem that the results, simply taken at face value, are regarded as representative of the bulk gold alloys of the objects analysed in museums and used for treasure analysis. It is well known that surface analysis is problematic, and the aim of this study was to test whether non‐destructive surface analysis could be useful in grouping the very large numbers of fragmentary pieces in the Anglo‐Saxon Staffordshire Hoard. Surface and subsurface analyses of 16 objects from the Hoard were carried out by X‐ray fluorescence (XRF) and scanning electron microscopy with energy‐dispersive X‐ray analysis (SEM–EDX). The results indicate that there are significant but inconsistent levels of enrichment of the gold at the surface of many of these objects, due to the loss of both copper and silver. The significant loss of silver (up to 50% relative in some cases) suggests that some form of deliberately induced depletion gilding was carried out during manufacture to remove both silver and copper from the surface. In three cases, an increase in silver at the surface compared to the core metal was detected: this might tentatively be explained by redeposition from contact with silver objects during burial. These results have clear implications for the reliability and interpretation of surface analysis data of gold alloys from this period.     

SOLDERING WITH GOLD ALLOYS IN ANCIENT SOUTH AMERICA: EXAMINATION OF TWO SMALL GOLD STUDS FROM ECUADOR

This paper presents the results of electron microprobe analysis of two gold studs, and their associated gold alloy solders. from La Tolita in Ecuador. Metallographic and compositional data are presented and the types of solders used are discussed.     

IS SCANNING ELECTRON MICROPROBE SUITABLE FOR COMPLETE ELEMENTAL ANALYSIS OF SOLDERS ON GOLD ARTIFACTS?

Summary. We comment on the inability of most scanning electron micro-probes equipped with energy dispersive solid state X-ray detectors to identify low amounts of cadmium in regions of solders on ancient artifacts. Traces of cadmium, even in the presence of high silver concentration determined with a nuclear microprobe, do not then contradict the results given by electron probes.     

Pretia Victoriae or Just an Occasional Bonus? Analysis of Iron Age Lead Artefacts from the Somerset Lake Villages

This paper looks at the evidence for the extraction of silver from lead ores in Iron Age and Roman Britain. Analysis shows that many of the lead objects from the Somerset Lake Villages were made from Mendip lead, but their chemical composition suggests that they were not produced from lead that had been de‐silvered, but from smelted galena with variable silver content. Furthermore, analysis of a Roman lead pig, made from Charterhouse lead ores, shows that it was made of chemically identical lead. Does this mean that silver was not extracted from British lead in the Iron Age and Roman periods? The evidence discussed and the results of the analyses suggest that silver was not always extracted from lead even when it was economical to do so. This was a cultural choice and not a technological limitation, one also found in other times and places around the world.     

X-ray fluorescence analysis of late Roman and Sassanian silver plate

About 200 analyses have been made on late Roman and Sassanian silver objects using energy-dispersive X-ray fluorescence. This has shown that the main feature of the composition of the silver throughout the period and across the geographical area studied was towards high fineness (average silver percentage about 95%). Compositional differences are found between Roman and Sassanian silversmiths' products for the elements copper and lead. Much of the material analysed came from hoards, and using a statistical technique on the analytical data (Discriminant Analysis) broad compositional differences between hoards were found to emerge. The use of different compositions of silver for different joined parts of a single object are discussed.     

Iron Age tin bronze metallurgy at Marlik,Northern Iran: an analytical investigation

The archaeological excavations performed in 1961 and 1962 at the necropolis of Marlik (Gilan District, northern Iran) revealed important archaeological remains dating to Iron Age I and II periods (late second/early first millennium BCE). While the metal collection from Marlik includes various gold, silver and bronze objects and is considered one of the most significant finds of metal objects from the prehistoric Iran, the technological investigations discussed in this paper provide information on tin bronze objects only from Marlik. Both the composition and the microstructure of 25 copper alloy objects have been determined in order to achieve a better understanding of the metallurgical processes used in northern Iran from the second to the first millennium BCE. Experimental analyses were carried out using inductively coupled plasma mass spectrometry (ICP-MS), scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS) and optical microscopy. The results demonstrated that the copper-base objects were made of the binary copper–tin alloy with variable tin contents. Other elements such as As, Ni, Pb, Zn and Sb were detected in minor/trace amounts. Variable tin content may be due to the application of an uncontrolled procedure to produce bronze alloy (e.g. co-smelting or cementation). Microscopic observations and microanalyses revealed the presence of numerous copper sulphide inclusions, lead globules and intermetallic phases scattered in the bronze solid solution. The microstructures seen in the bronze objects under study were varied and included worked/annealed or dendritic grain structures.     

Pre-Hispanic gold pieces of an enigmatic archaeological finding in Medellín,Colombia: A glance at an archaeometric analysis

The study analysed pre-Hispanic gold objects found within a surprising archaeological finding of a structure that likely served as a funeral pyre in Medellín, Colombia. ¹⁴C analyses of the site's organic materials dated the structure to the fifth century ce . The metal objects were subjected to X-ray diffraction (XRD), energy-dispersive X-ray fluorescence (EDXRF), scanning electron microscopy-energy dispersive X-ray (SEM-EDX), density measurement by the Archimedes method, and metallographic analysis. The measurements by EDXRF and SEM-EDX showed that the pieces were composed mostly gold and silver. The XRD results indicated that the microstructure of the objects corresponded to a single phase of gold and silver. The images obtained by the metallographic microscope showed equiaxial grains with some twins, a structure consistent with annealed metals. The different colours observed correspond to different grain orientations. Pre-Hispanic objects from a second archaeological site in the municipality of Amalfi (Department of Antioquia) were also analysed for comparative purposes. The results showed that the gold objects were not subjected to any alloying process, but were instead manipulated in their original form (native gold). The shape of the objects and their microstructural results suggested that the pieces were manufactured by casting, mechanical deformation and then annealing.     

Preliminary neutron diffraction study of two fenestrated axes from the ‘Enot Shuni' Bronze Age cemetery (Israel)

Neutron diffraction (ND) analyses of ancient metals show that this method is capable of detecting differences in the inner composition and microstructure of ancient metal objects. Here, ND measurements were conducted on two ‘eye shaped’ axes from the end of the 3rd-beginning of the 2nd millennium BC. The objects were excavated from the ancient cemetery of ‘Enot Shuni' Israel; one is made of bronze and the other of silver. Both artefacts are rare finds, with the silver axe unique in the archaeology of Israel, and therefore had to be analysed locally. For that purpose, a newly assembled diffractometer (KARL) at the IRR-1 of the Nuclear Research Centre (Soreq, Israel) was used. ND measurement on the bronze axe revealed the existence of an α-phase with a range of Cu/Sn ratios (Cu–Sn solid solutions) and some amount of a δ-phase (intermetallic compound of Cu and Sn). The silver axe ND pattern shows the existence of an α-phase (Ag–Cu solid solution) and some amount of copper metal. Our ND data are discussed in comparison with XRF surface measurements and thermal neutron radiography. The results are shedding more light on the in-depth material composition profile, as well as on the objects’ structural and compositional affinities, and help to better understand the production processes and assist in conservation decisions.     

Early Cambodian gold and silver from Prohear: composition,trace elements and gilding

Rescue excavations in Prohear, southeast Cambodia, recently saved the last untouched graves of one of the richest prehistoric sites in Southeast Asia. Many Iron Age burials dating from the 2nd century BC to the 1st century AD contained gold and silver ornaments so far unknown from archaeological contexts together with indications for the presence of an immigrated elite. A first selection of 59 objects were analysed by LA-ICP-MS to obtain detailed information about the composition, as well as minor and trace elements. The majority of the ornaments consist of electrum and auriferous silver with low copper concentrations, and two main groups indicating different alluvial gold sources can be distinguished by different concentrations of Pt, Ir, Bi and different Pd/Pt ratios, one group being related to rich burials with non-local features. The SEM and EDX analyses of four objects revealed two different gilding techniques observed for the first time in Southeast Asian artefacts: foil-fusion gilding, related to special Ag–Au–(Cu)–Sn alloys containing up to 4% tin, and depletion gilding.     

TECHNICAL STUDY OF A CEREMONIAL SICAN TUMI FIGURINE

Examination of a Sican ceremonial tumi, dated to the Middle Sican, c. AD 850–1050, showed that it was made in a silver-copper alloy of approximate composition 93% silver, 6% copper. Many separate pieces are used in the construction, joined together by both mechanical methods and by solder. The principal figure has been made from 18 separate silver sheets, with 169 separate parts identified in the head-dress, totalling 187 design elements. Metallographic examination of a fragment of repoussé decorated sheet from the figure surmounting the tumi surprisingly showed that the silver-copper alloy has a cast morphology; this demonstrates that Sican metalsmiths were pre-casting silver-copper sheet into the dimensions required for making the tumi, rather than carrying out the expected process of making the idol from hammered silver-copper sheet, shaped by extensive cycles of working and annealing, thus contradicting the usual assumptions about the manufacture of sheet-metalwork made in such cases.     

中国古代焊接技术初步研究

我国古代的多项金属技术都很早就取得了较高成就，但由于多方面原因，人们对我国古代焊接技术的发明、发展状况还是了解较少。本文主要依据考古实物的科学分析和文献研究，对此试作一初步探讨。...     

Early development of Jingdezhen ceramic glazes

Major types of ceramics produced in the history of Jingdezhen, from the Tang green glaze stoneware, through the Five Dynasties white ware, the Song dynasty bluish-white ware to the Yuan and Ming dynasties blue-and-white ware were analysed for their glaze chemistries to reveal, chemically, how the glazes of different periods in Jingdezhen evolved. Possible early period glaze recipes are proposed. Important events in the course of the technological development of Jingdezhen ceramic, such as the first use of limestone as a glaze flux, and how they may have impacted the way Jingdezhen ceramic technology advanced, are discussed.     

INVESTIGATION OF THE CONTENT OF ANCIENT TIBETAN METALLIC BUDDHA STATUES BY MEANS OF NEUTRON IMAGING METHODS

Many important cultural and religious objects from Asia consist of outer metallic shapes, usually bronze, which fully enclose inner contents made of organic materials such as wood, bark, paper, textile, plants and others. Bronze and other metallic materials, such as copper and silver, are generally more transparent to neutrons than to X‐rays. However, organic materials are less transparent to neutrons than to X‐rays and therefore organic materials, enclosed by metallic materials, can be made visible with neutrons. Therefore, neutron imaging (radiography and tomography) was found to be an ideal tool for the inspection of objects that consist of metal outside and organic materials inside. This has been successfully demonstrated here with four metallic Tibetan Buddha statues, providing archaeometry with a powerful new tool. The first successful applications of this novel technique are described in this article. Further possible and useful applications of neutron imaging of cultural objects are outlined.     

Ancient bronze technology and nomadic communities of the Middle Gobi Desert,Mongolia

The Xiongnu period of Mongolian prehistory (ca. 3rd century BC–AD 2nd century) is notable for the emergence of an expansive nomadic state and major changes in metallurgical and ceramic technologies. A number of Xiongnu period and pre-Xiongnu period bronze and bronze-related artifacts from the site at Baga Gazaryn Chuluu in the Middle Gobi province of Mongolia were examined for their chemical compositions and microstructures. They include finished objects, leftovers from casting, and pieces of slag from copper smelting and the assemblage likely represents a combination of local and regional production as well as long-distance exchange items. Results show that the entire bronze manufacturing process, from smelting to fabrication, is represented at BGC sites and bronze working may have been technologically self-sufficient, though ore sources are still uncertain. Our evidence suggests that this bronze assemblage was the result of two different technological traditions characterized by either the dominant use of arsenic, enforced apparently by restriction in tin supply, or the profuse use of both tin and lead. The arsenic-based tradition was observed in the majority of pre-Xiongnu period objects while the tin and lead recipes were verified in most objects dating to the Xiongnu period. This shift in bronze tradition may reflect changes in inter-regional interaction with frontier groups beyond the Gobi Desert and with the early state societies of China.     

Was Lacquer the Key Ingredient for Luxurious Jinyin Pingtuo Products in the Tang Dynasty of China (AD 618–907)?

Jinyin pingtuo is one of the most sumptuous decorative methods applied on ‘lacquered' objects described in Tang dynasty literatures. Two Tang dynasty objects, a silver bowl and a bronze mirror, in the British Museum collection said to be made by this technique, were scientifically examined to confirm the application of the technique. Although the metal décors levelled with the rest of the surfaces on these objects suggested the application of the pingtuo method, lacquer, a major ingredient of this technique, was not identified by Py (HMDS)-GC–MS in any of the four samples analysed. The results question the use of lacquer in the pingtuo technique as usually described. The detection of shellac and oil in the bronze mirror aligns with other studies on similar objects, whereas proteinaceous materials as main ingredient of the decorative layers of the silver bowl, appear less usual. Further comparative study by scientific analysis of similar objects in other museum collections or from excavations is required to help better understand the use of lacquer in ancient China.     

关于曾侯乙尊盘是否采用失蜡法铸造争论的述评

曾侯乙尊盘等青铜器是否采用失蜡法铸造工艺,是近来学术界一个热议的问题。本文通过对主张和否定两种观点的分析,指出过去确认尊盘为失蜡法工艺的论据不足。同时,否定说提出的一些反对意见,有多存在缺陷,否定说的核心观点--尊盘附饰上可见范缝和焊痕的说法,则是错误的。但尽管如此,曾侯乙尊盘是否采用失蜡法,则还需要进一步论证。     

Eighteenth‐Century Meissen Porcelain Reference Data Obtained By Proton‐Beam Analysis (PIXE–PIGE)

Prior to their restoration, the porcelain bodies of broken pieces from 31 authentic Meissen objects of the early 18th century were investigated by proton‐beam analysis. Attention was paid so that the proton beam probed only the bare porcelain paste areas of fractures. Thus, contributions to the measured X‐ray and γ‐ray spectra from adjacent surface glaze were prevented. The chemical compositions, obtained by simultaneous detection of elements with Z ≥ 13 (X‐rays) and lighter elements Z ≤ 14 (γ‐rays), represent rather consistent mixtures of paste ingredients. This result highlights the durable recipes and raw materials used in early Meissen porcelain production in the years 1725–50. Mean concentration values of element oxides, deduced from the detailed measurements, prove suitable for use as a database for Meissen porcelain paste identification. Material authentication of intact objects, without access to the bare porcelain body, is demonstrated by inspection of the white glaze. Unique museum objects are examined in atmosphere and without sampling. A low proton‐beam intensity and a short irradiation time ensure non‐destructive analysis. Simultaneous radiation and backscattered particle detection allow complete composition analysis, using the established ion beam techniques of particle‐induced X‐ray emission (PIXE), particle‐induced gamma‐ray emission (PIGE) and Rutherford backscattering spectrometry (RBS).     

唐代妇女发饰的技术分析与研究

近几年来为配合基本建设,在西安市长安区紫薇田园都市清理了一批唐墓,陆续出土了一些妇女发饰,其中有镂空鎏金花鸟纹银钗、银钗、鎏金花铜簪及散落的鎏金铜饰残片等。为了解当时的制作工艺及技术,对其进行了X射线能谱分析(EDS)和金相显微结构分析(SEM)。分析表明:1、2、5、6、7、8号样皆为银铜合金,3、4号样为铜合金;1、5、6、7、8号样的金相结构表现为重压冷锻组织,2、3号为退火组织。此项分析可为科学分析资料较少的金银器的研究提供参考和帮助。