POST‐MEDIEVAL CRUCIBLE PRODUCTION AND DISTRIBUTION: A STUDY OF MATERIALS AND MATERIALITIES*

This paper is concerned with the manufacture and trade of post‐medieval crucibles (14th–19th centuries). The analytical study of crucibles from different contexts in Europe and America employed optical microscopy and SEM–EDS, coupled with archaeological and historical data. We identified two major producers of crucibles, both of them in Central Europe, whose products appear widely distributed internationally. The analytical data allow an explanation of the technical reasons behind their superior reputation, as both crucible types shared comparable material properties, such as thermal, chemical and mechanical stability. Conversely, the two crucible types were radically different in their manufacture and appearance. We argue that, besides technical considerations, sensorial aspects such as texture and colour may have played an important role in the perception and choice of materials.     

On the origins of extractive metallurgy: new evidence from Europe

The beginnings of extractive metallurgy in Eurasia are contentious. The first cast copper objects in this region emerge c. 7000 years ago, and their production has been tentatively linked to centres in the Near East. This assumption, however, is not substantiated by evidence for copper smelting in those centres. Here, we present results from recent excavations from Belovode, a Vin?a culture site in Eastern Serbia, which has provided the earliest direct evidence for copper smelting to date. The earliest copper smelting activities there took place c. 7000 years ago, contemporary with the emergence of the first cast copper objects. Through optical, chemical and provenance analyses of copper slag, minerals, ores and artefacts, we demonstrate the presence of an established metallurgical technology during this period, exploiting multiple sources for raw materials. These results extend the known record of copper smelting by more than half a millennium, with substantial implications. Extractive metallurgy occurs at a location far away from the Near East, challenging the traditional model of a single origin of metallurgy and reviving the possibility of multiple, independent inventions.     

Did China Import Metals from Africa in the Bronze Age?

The origins of the copper, tin and lead for China's rich Bronze Age cultures are a major topic in archaeological research, with significant contributions being made by archaeological fieldwork, archaeometallurgical investigations and geochemical considerations. Here, we investigate a recent claim that the greater part of the Shang‐period metalwork was made using metals from Africa, imported together with the necessary know‐how to produce tin bronze. A brief review of the current status of lead isotopic study on Shang‐period bronze artefacts is provided first, clarifying a few key issues involved in this discussion. It is then shown that there is no archaeological or isotopic basis for bulk metal transfer between Africa and China during the Shang period, and that the copper and lead in Shang bronze with a strongly radiogenic signature is not likely to be from Africa. We call for collaborative interdisciplinary research to address the vexing question of the Shang period's metal sources, focusing on smelting sites in geologically defined potential source regions and casting workshops identified at a number of Shang settlements.     

Metallurgical traditions and metal exchange networks in late prehistoric central Myanmar,c. 1000 BC to c. AD 500

Myanmar has been notably underrepresented in recent studies of archaeometallurgy in Southeast Asia, despite its richness in both mineral and cultural resources and its potentially central role in long-distance exchange networks linking India, China and peninsular neighbours. Here, we present original analytical data on copper-base artefacts from several Bronze Age and Iron Age sites in Myanmar. Observed microstructures range from as-cast, worked, to fully annealed; compositions include leaded copper, low-tin to high-tin bronzes, and arsenical copper/bronze. Lead isotope analyses indicate that the metal originates from different geological sources, including several that match the lead isotope signatures of known prehistoric copper mines in Thailand and Laos. These archaeometallurgical data, including evidence for secondary copper-base production, more than double those currently available for Myanmar and document the presence of multiple local alloying and working traditions, perhaps chronologically differentiated, as well as identifying possible links to primary mineral sources across the region. Overall, this adds significant new information to the emerging picture of Southeast Asian prehistoric metallurgy at the crossroads of several major ancient cultures.     

Explaining the evolution of ironmaking recipes – An example from northwest Wales

Building on insights from previous Darwinian studies of technology, this paper explores the potential of evolutionary models to explain diversity and change in bloomery ironmaking recipes. Bloomery, or direct process ironmaking, involves the solid state reduction of iron oxide to metal and was the predominant means of producing iron in the pre-industrial world. The most archaeologically accessible record of bloomery practice is slag, an essential by-product of the smelting process. Ironmaking recipes can be characterized by their slag chemistry using a combination of multivariate statistics, ternary phase diagrams, and oxide ratios. Models derived from evolutionary theory are used to explain the shape, structure, and trajectories of ironmaking lineages identified from patterns of slag chemistry in terms of invention, selection, and socially mediated constraint processes. The utility of this approach is demonstrated by its application to slag excavated at Llwyn Du, a late medieval bloomery in northwest Wales.     

Western technical traditions of pottery making in Tang Dynasty China: chemical evidence from the Liquanfang Kiln site,Xi'an city

This study is based on the SEM-EDS and LA-ICP-AES analyses of a sample of twenty-nine Tang sancai sherds unearthed from the Liquanfang site, Xi'an city. The results indicate that ceramics with yellowish bodies are calcareous and those with red bodies were made of ferruginous clays. The use of calcareous clay in Tang sancai bodies is otherwise unknown in Chinese history, which suggests that the technique of Tang sancai making at this site might have been influenced by ceramic technology from the Near East or Central Asia. The paper therefore argues that the traditional approach of treating calcareous clay as the main characteristic of pottery made in the ancient Near East or Central Asia is not necessarily accurate. It is likely that some calcareous Tang sancai ceramics were made in the capital city of the Tang dynasty.     

Large scale smelting of speiss and arsenical copper at Early Bronze Age Arisman,Iran

We report analyses of different slag types found at the Early Bronze Age site of Arisman in North-West Iran. Here, an estimated 20 tons of slag provide evidence of sustained and large-scale production of metal, using both furnaces and crucibles. The results show that both speiss, an iron-arsenic alloy, and arsenical copper were produced, apparently side-by-side at the same site but using different ores and processes. We offer a tentative outline of the metallurgical processes involved in the production of these arsenic alloys and an explanation why speiss needed to be produced from arsenopyrite in a separate step, instead of using the mineral in its native form as a source for arsenic. We suggest that the speiss was then added either to secondary copper ore or to separately smelted copper metal, in order finally to produce arsenical copper in a regular and well-controlled process.