On Pins and Needles: Tracing the Evolution of Copper-base Alloying at Tepe Yahya, Iran, via ICP-MS Analysis of Common-place Items

From 1967 to 1975 a team of archaeologists excavated the site of Tepe Yahya in southeastern Iran under the direction of C. C. Lamberg-Karlovsky. Although there are two forthcoming “final reports” (Hiebert (in progress), and Magee (in press); see also Lamberg-Karlovsky & Potts, 2001), analysis of the materials continues as opportunities allow. Metal artefacts, most especially those made of copper and its alloys, are found at this site from the late Neolithic through the Iron Age. Archaeometallurgical analysis, radiocarbon chronologies, and archaeological interpretation allow one to state when and how a type of metal or a style of object was invented, its use as a trade item, and its function and value to an ancient community. In the hopes of establishing a framework for future archaeometallurgical studies, most of the metal artefacts from Tepe Yahya, Iran, stored in the Peabody Museum of Harvard University, were analysed for elemental composition to complement stylistic and metallographic data.     

ANALYTICAL INVESTIGATION OF ARCHAEOLOGICAL POWDERS FROM GÖLTEPE (TURKEY)*

Nine powder samples originating from the archaeometallurgical she in Göltepe, southern central Turkey, have been analysed. Bulk analyses, using X-ray fluorescence and X-ruy photoelectron spectroscopy, and single particle analyses, using electron probe X-ray microanalysis, were carried out. The analyses were focused on determining the inorganic elemental composition of the samples and the distribution of particle types in the nine powder samples. In addition, the powder samples were classified on the basis of their elemental composition using multivariate techniques. The objective of this study was to characterize the powder samples and to establish an association with archaeological data from the site     

IDENTIFICATION AND DIFFERENTIATION OF OPAQUE CHINESE OVERGLAZE YELLOW ENAMELS BY RAMAN SPECTROSCOPY AND SUPPORTING TECHNIQUES*

Using Raman spectroscopy, energy-dispersive X-ray fluorescence and X-ray diffraction, the Pb–Sn–Sb triple oxide yellow and lead–tin yellow have been identified on two pieces of cloisonné enamel (Falangcai) porcelains. Lead–tin yellow and lead antimonate yellow have been identified on famille rose porcelains manufactured before and after 1911, respectively. The replacement of the Pb–Sn–Sb triple oxide yellow by lead–tin yellow and that of the lead–tin yellow by lead antimonate yellow are discussed.     

ANTIMONATE OPAQUE GLAZE COLOURS FROM THE FAIENCE MANUFACTURE OF LE BOIS D’ÉPENSE (19TH CENTURY,NORTHEASTERN FRANCE)*

Three types of antimony‐based, opaque ceramic colours were used in the faience workshop of Le Bois d’Épense during the first decades of the 19th century; that is, yellow, tawny and green. Yellow is generated by lead antimonate crystals (Naples Yellow), which are incorporated into an uncoloured glass matrix. According to SEM–EDS measurements, these pigments contain iron. The tawny colour is the optical result of the combined presence of similar yellow, iron‐bearing lead antimonate particles in a Fe‐rich, brownish glass matrix. The green opaque colour is produced by the combination of a blue cobalt glass and yellow Pb–Sn–Fe‐antimonate crystals. Cores of zoned pigments lighten the recipes, according to which the pigments were produced. First, they were synthesized by calcination, ground and then mixed with a colourless, brown or blue glass powder. The resulting powder mixture was added to a liquid agent and used as high‐temperature ceramic colour.     

EARLY BRONZE AGE TIN PROCESSING AT KESTEL/GÖLTEPE,ANATOLIA

Chemical analysis of statistically significant numbers of samples including minerals, sediments, soil, host rock as well as powdered materials, crucible accretions and metal artefacts revealed information about the distribution of cassiterite at Kestel and the tin smelting processes that took place at Göltepe c. 2600 BC. Using the ancient technique of vanning for the isolation of tin ore (cassiterite), followed by assaying by blowpipe/charcoal block, as well as crucible smelting with a blowpipe, good tin metal suitable for alloying with copper to make bronze was obtained. There is every indication that tin was mined and smelted in the Early Bronze Age at the Kestel/Göltepe sites.     

TIN ISOTOPY—A NEW METHOD FOR SOLVING OLD QUESTIONS

Tin was a vital commodity in times past. In central Europe, the earliest finds of tin‐bronze date to about 2200 bc , while in Greece they are c. 400–500 years earlier. While there is evidence for prehistoric copper mining—for example, in the Alps or mainland Greece, among other places—the provenance of the contemporary tin is still an unsolved problem. This work deals with a new approach for tracing the ancient tin via tin isotope signatures. The tin isotope ratios of 50 tin ores from the Erzgebirge region (D) and 30 tin ores from Cornwall (GB) were measured by MC–ICP–MS. Most ore deposits were found to be quite homogeneous regarding their tin isotope composition, but significant differences were observed between several deposits. This fact may be used to distinguish different tin deposits and thus form the basis for the investigation of the provenance of ancient tin that has been sought for more than a century. Furthermore, the tin‐isotope ratio of the ‘Himmelsscheibe von Nebra’ will be presented: the value fits well with the bulk of investigated tin ores from Cornwall.     

COPPER AND BRONZE DURING THE ENEOLITHIC AND EARLY BRONZE AGE: A METALLOGRAPHIC EXAMINATION OF AXES FROM THE NORTHALPINE REGION*

This paper presents the results of a metallographic examination of Eneolithic and Early Bronze Age axes from the Northalpine region of central Europe. During this period, different types of copper were in use: arsenical copper, Fahlerz copper and tin bronze. We examine if and to what extent the different properties of the metals used were known to prehistoric metalworkers and actively manipulated in the production of the axes. The development of methods of casting and smithing is discussed. Both aspects contribute to our understanding of the nature of prehistoric technological change. During the Early Bronze Age of the Northalpine region, different traditions of early metallurgy can be identified, which differ in their use of Fahlerz copper, their attitude towards tin alloying and the use made of tin bronze in the production of the axes. These traditions can only be adequately described by reference to both composition—that is, access to different types of copper as well as tin—and knowledge of the production techniques provided by metallographic data.     

THE TECHNOLOGY OF GLAZED ISLAMIC CERAMICS USING DATA COLLECTED BY THE LATE ALEXANDER KACZMARCZYK

During the 1980s, the late Alexander Kaczmarczyk undertook the analysis of some 1200 glazed Islamic ceramics from Egypt, Iran, Iraq and Syria spanning the period from the eighth to the 14th centuries ad , using a combination of XRF for the glazes, and AAS or PIXE for the bodies. The aim of the present paper is, first, to bring to the attention of researchers into Islamic ceramics the fact that these analytical data are available on the Research Laboratory for Archaeology and the History of Art website, and also that some 400 of the analysed sherds are held in the Research Laboratory. Second, the paper provides a preliminary interpretation of the analytical data in terms of the choice of glaze type (i.e., alkali–lime, lead–alkali and high‐lead), tin‐opacification, body type (i.e., quartz or stonepaste, calcareous clay, and non‐calcareous clay), and colorants.     

The production technology of Iznik pottery—a reassessment*

Previous research has established that Iznik pottery differs from other Islamic stonepaste pottery in that its stonepaste bodies contain lead oxide as well as soda and lime, and that a significant proportion of the tin oxide in its glaze is present in solution rather than as tin oxide particles. In order to better understand these distinguishing features, the chemical compositions and microstructures of Iznik pottery and tile samples, together with those of lumps of glass found in association, were investigated using both scanning electron and optical microscopy. These data have been supplemented by the study of replicate lead–alkali glazes produced in the laboratory with a range of different compositions. The results demonstrate that separate soda–lime and high‐lead glasses were used in the production of Iznik stonepaste bodies, and that the total glass contents of the bodies were significantly higher than those quoted by Abū’l‐Qāsim, who was writing in about ad 1300. The very high purity of the lead–soda Iznik glazes indicated that the alkali flux used was either a purified plant ash or an as yet unidentified mineral source of soda. Replication experiments established that the high solubility of tin oxide in the glaze was due to the high purity of the glaze constituents. Furthermore, it is suggested that tin oxide was added to the glaze in order to give it a very slight opacity and thus obscure any blemishes in the underlying body.     

ROMANO‐EGYPTIAN RED LEAD PIGMENT: A SUBSIDIARY COMMODITY OF SPANISH SILVER MINING AND REFINEMENT*

Samples of red pigment from a group of seven Roman‐period Egyptian mummies, known as red‐shroud mummies, are investigated. Elemental analysis by inductively coupled plasma time‐of‐flight mass spectrometry (ICP–TOFMS) shows that the samples contain mostly Pb (83–92% by weight), along with 0.2–2.0% Sn. All of the samples are found to have similar trace element distributions when normalized to the continental crust, suggesting that they share a common geological origin. Lead isotope ratios are found to match the mixed lead sources typically associated with Rio Tinto, Spain – a site extensively mined for silver during the first century ad . Raman microspectroscopy identifies the major phase of each sample to be red lead (Pb₃O₄) with a minor phase of lead tin oxide (Pb₂SnO₄). Lead tin oxide does not occur naturally, and its incidental occurrence within the sample indicates that the material was heated under oxidative conditions at temperatures in excess of 650°C. In archaeological contexts, the high‐temperature oxidative treatment of lead is typically associated with metallurgical refinement processes such as cupellation. Based on this evidence, it is argued that the pigment was produced out of litharge associated with silver cupellation at the Rio Tinto site.