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.     

The earliest high-fired glazed ceramics in China: the composition of the proto-porcelain from Zhejiang during the Shang and Zhou periods (c. 1700–221 BC)

Bodies and glazes of 54 proto-porcelain sherds and 18 non proto-porcelain samples from Shang and Zhou periods production sites in Deqing, Zhejiang province were analysed by EPMA-WDS. The results indicate that the bodies of all samples were made from local raw material – porcelain stone, with the proto-porcelain samples being made from clay of higher quality. Wood ashes, high in lime and low in potash, were intentionally applied to the proto-porcelain samples, resulting in the formation of lime-rich glazes whose compositions were determined by a temperature-controlled mechanism. In contrast, kiln fragments and furniture show a potash-rich fuel vapour glaze, which formed unintentionally during use of the kiln. The firing temperature for most of the proto-porcelain glazes is around the maturing temperature for typical more recent lime glazes, showing that the potters were already at such an early time able to attain sufficiently high temperature in their kilns.     

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.     

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.     

THE BLACK INLAY DECORATION ON A MYCENAEAN BRONZE DAGGER*

The black inlay decoration with superb marine, hunting and other scenes on Mycenaean bronze daggers and silver cups has often been referred to in the literature as niello—a mixture of sulphides of copper, silver or lead—despite the absence of any systematic analysis of these precious metal artefacts. This paper presents semi-quantitative surface analyses of an example of black inlay on a Mycenaean dagger, now in the Archaeological Museum at Patras in Greece. Using non-destructive X-ray fluorescence spectrometry, it has been established that, contrary to the traditionally-held view, the black inlay is a copper-gold alloy with some silver and possibly small amounts of tin.     

Lisht as a New Kingdom Glass‐Making Site with Its Own Chemical Signature

Lisht is one of a few New Kingdom sites with known glass‐working debris. Here, we present evidence for the primary production of glass at Lisht, including crucible fragments and semi‐finished glass. We also provide 12 new chemical analyses of glass from Lisht, including trace elements. We argue that the glass made at Lisht has a specific chemical signature within the broader range of Late Bronze Age glass compositions from Egypt, further underlining the former existence of primary glass production there and offering the possibility of identifying Lisht‐made glass elsewhere in Egypt and beyond.     

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.     

Ores, Furnaces, Slags, and Prehistoric Societies: Aspects of Iron Working in the Nyanga Agricultural Complex, AD 1300–1900

The Nyanga agricultural complex through its cultivation terraces and ridges represents one of the most intensified agricultural systems in southern African prehistory. In such a well developed system of land management and use, iron tools played a crucial role in clearing the land for cultivation as well as for domestic building purposes. Important to this dimension is the need to understand iron production and use in prehistoric societies. This paper aims for the first time to look at iron technology in the Nyanga agricultural complex through an initial analysis of iron extraction remains such as ore, slag, and furnace fragments. As a result, the technical data obtained will be used to develop hypotheses which future research can engage. This paper is a preliminary statement toward developing an understanding of iron production to meet various purposes from the deeper past to the historical period.Le complexe agricole Nyanga avec ses terrasses et collines cultivées représente un des systèmes agricoles les plus intensifs de la préhistoire de l'Afrique du sud. Dans ce système d'organisation et d'exploitation bien développé les outils en fer jouent un rôle important dans la cultivation du sol et la construction des bâtiments. Il est nécessaire de bien connaître les méthodes de production et d'utilisation du fer dans les sociétés préhistoriques. Cet article traite pour la première fois de la technologie du fer dans le complexe agricole Nyanga en présentant des analyses préliminaires des restes de l'exploitation du fer tels les minerais, les scories et les fragments de fourneaux. Les résultats de l'étude de ces techniques vont servir à développer des hypothèses qui aideront à faire avancer les recherches futures. Cet article représente un essai préliminaire pour développer nos connaisaences sur la production du fer destiné à de multiples usages depuis les temps les plus reculés jusqu à la période préhistorique.     

Melt formation in lime-rich proto-porcelain glazes

Early Chinese lime-rich glazes form an important step in the development of high-fired ceramics. This experimental study, based on the analysis of archaeological samples of proto-porcelain and replicated samples, explores the role of ash and glaze mixture preparation, firing temperature and duration, and cooling protocol for the quality and composition of the resulting glaze. It is demonstrated that the application of raw wood ash rich in potash produces low-potash glazes, that the melt formation follows a cotectic mechanism which needs extended firing times to reach equilibrium, and that the formation of a crystalline interaction layer depends more on the kiln cooling history and high-temperature soaking than on the glaze application method.