Effects of alloy composition in traditional Japanese shakudo patination.

Japanese craftspeople have dominated the art of patinating copper-alloys since the 15th century, using precise alloy compositions and complicated patination processes in different hot solutions to create a variety of colours on swords fittings such as tsuba. While this complex tradition is increasingly popular in the East, the reasons behind the choices made by craftspeople in the selection of the components of the alloys and are still not fully understood. This paper investigates the effect of different alloying elements (tin, gold, and silver) on the resulting patina. Experimental results are compared with optical and compositional analyses on historical Japanese artefacts, confirming the effects of the different alloying elements on the patina characteristics and colour. The absence of tin and the presence of gold limit the growth of an oxide layer and promote the formation of a thin patina characterised by a smooth appearance without visible grains. Therefore, a limited thickness of the patinas is a key aspect for the production of the desired colour and appearance of the patinas. The first colorimetric analysis on historical Japanese artefacts demonstrates the influence of gold, silver and tin in the final patina colour, validating the observations in the experimental replicas.

The casts of Pompeii: Post-depositional methodological insights.

The casts of Pompeii bear witness to the people who died during the Vesuvius 79 AD eruption. However, studies on the cause of death of these victims have not been conclusive. A previous important step is the understanding of the post-depositional processes and the impact of the plaster in bones, two issues that have not been previously evaluated. Here we report on the anthropological and the first chemical data obtained from the study of six casts from Porta Nola area and one from Terme Suburbane. A non-invasive chemical analysis by portable X-ray fluorescence was employed for the first time on these casts of Pompeii to determine the elemental composition of the bones and the plaster. Elemental profiles were determined providing important data that cross-referenced with anthropological and stratigraphic results, are clearly helpful in the reconstruction of the perimortem and post-mortem events concerning the history of these individuals. The comparative analyses carried out on the bone casts and other collections from burned bones of the necropolis of Porta Nola in Pompeii and Rome Sepolcreto Ostiense, and buried bones from Valencia (Spain), reveal the extent of high temperature alteration and post-depositional plaster contamination. These factors make bioarchaeological analyses difficult but still allow us to support asphyxia as the likely cause of death.

Archaeological science, globalisation, and local agency: gold in Great Zimbabwe.

Great Zimbabwe (CE1000-1600) is world famous for outstanding cultural innovations and localised and globalised entanglement with trans-Africa and trans-Indian Ocean exchange. New excavations yielded fragments of over a hundred gold processing vessels comprising reused pottery and purpose-made crucibles from stratified contexts in the Eastern Ridge Ruins and adjacent areas. Selected samples were studied using archaeological, microscopic, and compositional (SEM-EDS) techniques. All ceramics were made of alumina-rich clays and contain minerals common to granite-derived lithologies typical of the area, although it is possible that particularly refractory clays were selected to make crucibles locally. These technical ceramics were used for refining and collecting gold at high temperature, most likely producing not only relatively standardised ingots but also finished objects. The composition of the gold prills set in crucible slag is consistent with that of natural, unalloyed gold, while the variability in silver levels and minor impurities point to heterogeneous sources of the gold. Considering these finds in their multiple site and regional contexts, and together with complementary threads of information from early reports of antiquarians and looters, we argue that local agency and gold consumption were much more significant than generally assumed. The conclusion to the paper is that Great Zimbabwe's famous participation in local and global exchanges was backed by internally driven but improvisation laden production and consumption occurring in homesteads located throughout its various settlements. We end by raising a word of caution about oversimplified narratives of globalisation and their archaeological expressions (see Supplementary Material S0 for the abstract in Shona). Supplementary Information: The online version contains supplementary material available at 10.1007/s12520-023-01811-7.

Smelting copper in decorated pottery: communities of practice in the Niari Basin, Republic of the Congo, fifteenth-seventeenth centuries CE.

This paper considers copper production in the Niari Basin, Republic of the Congo, during a period dated to the mid-fifteenth-mid-seventeenth centuries CE. Using a combination of pXRF, OM, SEM-EDS, and FTIR, it assesses the microstructure and composition of slags and technical ceramics from sites associated with two different regional pottery traditions: Moubiri-type at the site of Kingoyi near Mindouli and Kindangakanzi-type at Kindangakanzi near Boko-Songho. Both sites are characterised by the use of refractory domestic pottery as crucibles for copper smelting. Moubiri-type pottery is alumina-rich, while Kindangakanzi-type pottery is formed from a magnesia-rich clay, a crucible type unique in sub-Saharan Africa. Similarities in chaînes opératoires at Kingoyi and Kindangakanzi suggest sharing of knowledge at mining and smelting sites, interactions we reconstruct as a metallurgical constellation of practice comprised of the distinct potting communities of practice (see Supplementary information for abstract in Lingala and French). Supplementary Information: The online version contains supplementary material available at 10.1007/s12520-022-01653-9.

The Old Ashmolean Museum and Oxford's Seventeenth-Century Chymical Community: A Material Culture Approach To Laboratory Experiments.

Towards the end of the seventeenth century, Oxford's chymical community came together in the Ashmolean Museum. Founded in 1683, the institution was part of Oxford University and home to the first official chair of chymistry in the country, with practical teaching directed by Robert Plot in the basement laboratory. The information at our disposal is scarce and Plot did not leave us detailed accounts of his laboratory work. However, a large assemblage of ceramic crucibles and distillation apparatus was recovered from the site where the laboratory once operated, an invaluable material perspective on the experimental agenda of one of the most important chymical laboratories in early modern Europe. The scientific analysis of the materials indicates that the work focused on technological innovation in the fields of glassmaking, specialised pottery, and zinc metallurgy, and shows how the laboratory kept close contact with some renowned artisan-entrepreneurs of the time. We argue that material culture offers an informative perspective on chymical practice in and beyond Oxford. The results provide fresh insight into the Old Ashmolean Museum, an institution that grew out of the Baconian spirit, where doing chymistry meant working at the intersection of artisanal and scholarly worlds.

Interwoven traditions in Bell Beaker metallurgy: Approaching the social value of copper at Bauma del Serrat del Pont (Northeast Iberia).

Debates on early metallurgy in Western Europe have frequently focused on the social value of copper (between utilitarian and symbolic) and its purported role in the emergence and consolidation of hierarchies. Recent research shows that generalisations are increasingly untenable and highlights the need for comparative regional studies. Given its location in an intermediate area, the early metallurgy of Northeast Iberia provides an interesting case in point to explore the interaction between the well-characterised traditions of southern Iberia and southern France during the 3rd and 2nd millennia BCE. Here the analytical study of seven Bell Beaker (decorated and undecorated) vessels reused as crucibles at Bauma del Serrrat del Pont (Tortellà, Girona) are presented. We employed pXRF, metallography, SEM-EDS and lead isotope analyses. The results show evidence for copper smelting employing a remarkable variety of ore sources, including Solana del Bepo, Turquesa and Les Ferreres mines, and an extra unknown area. The smelting vessels were manufactured using the same clay, which contained both mineral and organic inclusions. Our results are discussed with reference to all the evidence available for metals and metallurgy in the Northeast, and more broadly in comparison to southern Iberia and southern France, with special emphasis on issues of production organisation and social complexity. Taken together, our results support the notion that copper metallurgy played a predominantly utilitarian role in Bell Beaker societies and highlight idiosyncratic aspects of the metallurgical trajectory in the Northeast. Differences between territories challenge unilinear explanations of technological and social development after the introduction of metallurgy. Separate trajectories can only be explained in relation to area-specific socio-cultural and environmental factors.

Reverse engineering of ceramic anthropomorphic figurines from the Tumaco archaeological tradition in southwest Colombia.

Traditional studies of archaeological ceramics in Colombia have been largely based on visual and stylistic analyses. Here we introduce frameworks and concepts of reverse engineering as a complementary strategy to develop hypotheses about ceramic manufacture, as a first step to the address possible cross-craft relationships and broader sociocultural parameters affecting technical traditions. Our case study is focused on ceramic figurines recovered from two archaeological sites in southwest Colombia (Inguapí and La Cocotera), both dated to the period of greatest cultural and technological development of the Tumaco tradition (350 BC-AD 350). The results of the analyses including microscopy, XRF, SEM-EDS and XRD revealed two manufacturing pathways within the broader tradition, developed locally and adapted to the natural resources available to each site. These are shown through chemical and mineralogical differences in the raw materials, as well as differences in their preparation and shaping, molding, and modeling processes as observed at the microstructural level. Estimated firing temperatures are under 600°C for La Cocotera, and under 800°C for those of Inguapí, with an inhomogeneous, oxidizing atmosphere probably related to firing in a pit. The superficial characterization shows that all the figurines were painted, with those from Inguapí externally smoothed and polished, and those from La Cocotera covered with a slip. Notwithstanding differences between sites, the ceramic figurines illustrate a particular technical style that undoubtedly conveyed a shared ideological message of cultural affiliation. These results contribute in an innovative way to archaeological ceramic studies in Colombia from a different perspective that is complementary to the more common typological studies.

Surface chromium on Terracotta Army bronze weapons is neither an ancient anti-rust treatment nor the reason for their good preservation.

For forty years, there has been a widely held belief that over 2,000 years ago the Chinese Qin developed an advanced chromate conversion coating technology (CCC) to prevent metal corrosion. This belief was based on the detection of chromium traces on the surface of bronze weapons buried with the Chinese Terracotta Army, and the same weapons' very good preservation. We analysed weapons, lacquer and soils from the site, and conducted experimental replications of CCC and accelerated ageing. Our results show that surface chromium presence is correlated with artefact typology and uncorrelated with bronze preservation. Furthermore we show that the lacquer used to cover warriors and certain parts of weapons is rich in chromium, and we demonstrate that chromium on the metals is contamination from nearby lacquer after burial. The chromium anti-rust treatment theory should therefore be abandoned. The good metal preservation probably results from the moderately alkaline pH and very small particle size of the burial soil, in addition to bronze composition.

Amber in prehistoric Iberia: New data and a review.

Provenancing exotic raw materials and reconstructing the nature and routes of exchange is a major concern of prehistoric archaeology. Amber has long been recognised as a key commodity of prehistoric exchange networks in Europe. However, most science-based studies so far have been localised and based on few samples, hence making it difficult to observe broad geographic and chronological trends. This paper concentrates on the nature, distribution and circulation of amber in prehistoric Iberia. We present new standardised FTIR analyses of 22 archaeological and geological samples from a large number of contexts across Iberia, as well as a wide scale review of all the legacy data available. On the basis of a considerable body of data, we can confirm the use of local amber resources in the Northern area of the Iberian Peninsula from the Palaeolithic to the Bronze Age; we push back the arrival of Sicilian amber to at least the 4th Millennium BC, and we trace the appearance of Baltic amber since the last quarter of the 2nd Millennium BC, progressively replacing Sicilian simetite. Integrating these data with other bodies of archaeological information, we suggest that the arrival of Baltic amber was part of broader Mediterranean exchange networks, and not necessarily the result of direct trade with the North. From a methodological perspective, thanks to the analyses carried out on both the vitreous core and the weathered surfaces of objects made of Sicilian simetite, we define the characteristic FTIR bands that allow the identification of Sicilian amber even in highly deteriorated archaeological samples.

Glass and Alchemy in Early Modern Europe: An Analytical Study of Glassware from the Oberstockstall Laboratory in Austria.

Glass distillation equipment from an early modern alchemical laboratory was analyzed for its technology of manufacture and potential origin. Chemical data show that the assemblage can be divided into sodium-rich, colorless distillation vessels made with glass from Venice or its European imitation, and potassium-rich dark-brown non-specialized forms produced within the technological tradition of forest glass typical for central and north-western Europe. These results complete our understanding of the supply of technical apparatus at one of the best-preserved alchemical laboratories and highlight an early awareness of the need for high-quality instruments to guarantee the successful outcome of specialized chemical operations. This study demonstrates the potential of archaeological science to inform historical research around the practice of early chemistry and the development of modern science.

Inside Solomon's house: an archaeological study of the Old Ashmolean chymical laboratory in Oxford.

This paper is based on the archaeological and analytical study of the laboratory remains from the Officina Chimica of the Old Ashmolean Museum in Oxford. Following a contextualisation of this laboratory, founded in the wake of Bacon's utopian idea of Solomon's Temple, it is argued that the assemblage is likely to date from the late seventeenth century and thus be connected to the work of Robert Plot, Christopher White, and, indirectly, Robert Boyle. The analytical study of the equipment reveals that the chymists at the Old Ashmolean obtained crucibles from the best manufacturers in Europe, and that they used these and other utensils for experiments involving mercury, sulphur, zinc, lead glass, manganese, and antimony. The importance of these elements for early modern chymistry is discussed in the light of relevant historical sources, including some of Boyle's chymical texts. Altogether, these finds illustrate some of the rich diversity of experiments that took place in one of the most prominent laboratories of the period, showing strong connections with longstanding alchemical concerns as well as with cutting-edge research and development ventures.

Some recent developments in the historiography of alchemy.

The number of researchers and publications devoted to the history of alchemy has seen exponential growth and diversification in recent decades, to such an extent that some scholars speak of a "New Historiography of Alchemy". On the occasion of the seventy-fifth anniversary of the Society for the History of Alchemy and Chemistry, this paper outlines some highlights of the literature since 1990, with a view to identify current trends but also challenges for the future. Some of the most important changes identified are a marked awareness of the risks of presentism, a shift from ambitious histories to contextualised microhistories, a heightened recognition of the internal diversity of historical alchemy, and a greater emphasis on its practical dimensions and its role in the Scientific Revolution. Among the challenges, the paper underscores the potential risks of an excessive historiographical fragmentation, the need for further interdisciplinary training and cooperation, and the responsibilities of alchemy historians towards students and the general public alike.