Archaeometallurgy of Copper

The creative ways in which native North American peoples of the Eastern Woodlands utilized copper throughout prehistory present provocative contrasts to models of Old World metallurgical development. Archaeological approaches that incorporate laboratory methods into investigations of indigenous metalworking practice have brought new insights and raised new questions about the development and use of techniques, sources of materials, and the social dynamics of copper consumption. This paper integrates the results of these studies into a discussion of copper use in Old Copper, Hopewellian, and Mississippian traditions that focuses on illuminating the complex relations among levels of technological sophistication in the manipulation of the material itself, the often elaborate and meaning-laden contexts in which artifacts were used, and the relative social complexity of the cultures that supported copper procurement, transformation, and use. It is suggested that 'technological style' approaches will assist archaeologists in efforts to flesh out culture-specific aspects of its consumption.

Article by: Christos N. Kleitsas - M. Mehofer - R. Jung
The hoard of Stephani in Preveza is a closed assemblage of artefacts that contains two stone and fifteen bronze, mainly broken, tools or-and weapons (ten bronze double-edged axes, one bronze leaf-shaped spearhead and two other badly damaged, two bronze unidentifiable cylindrical pointed rods, as well as two stone tools or whetstones). It was probably hidden away to be retrieved at a later date, something that was never accomplished. Accidentally discovered in 1985 by the farmer Theodoros Kritsimas in a fissure of limestone rocks, across the hilly area that extends between the townlets Stephani and Louros, the hoard was subsequently handed over to the appellate authorities and the appropriate financial reward was eventually granted. The Stephani hoard is on display in the showcase of the Bronze Age in the prehistoric gallery of the renovated Archaeological Museum of Ioannina, along with the other known hoard of seven bronze objects from Katamachi in Ioannina and other primarily Late Bronze Age finds from Epirus. In this interdisciplinary article we present various archaeological and analytical results (XRF, lead-isotope analyses, metallography) of the artefacts under study.

Am Ende des Äneolithikum bzw. am Anfang der Frühen Bronzezeit treten Nachweise der Verhüttung kupferhaltiger Erze in verschiedenen Orten innerhalb des alpinen Raums auf (z.B. Höppner et al., 2005;. Im Laufe der Frühen Bronzezeit (FB I-IIa ca. 2200-1800 BC), nahm die Benutzung von Kupfer und seiner Legierungen in Europa rapide zu und als Folge gab es eine fast exponentielle Steigerung der Kupferproduktion. Diese intensive Ausbeutung hinterließ deutliche Spuren in der Landschaft, nicht nur in Form von ober-bzw. untertägigen Abbaustellen, sondern auch von zahlreichen Schmelzplätzen, welche die Bergbaureviere umgeben. Solche Schmelzplätze können eine besondere Herausforderung für Archäologinnen darstellen, da einige thermochemische Prozesse berücksichtigt werden müssen, um die Befunde richtig zu interpretieren und sie an den entsprechenden Stellen in den Arbeitsablauf einzuordnen.

Recent analyses carried out on objects with polychrome decoration found in various regions of the Roman Empire and dated to the 1st century CE, identified an array of patinated alloys similar to the classical Japanese irogane alloys. The inlays, the technical details and the motives of the decorative figures represented on the magnificent pieces studied for this research indicate a Romano-Egyptian provenance. Similarities in motives, composition and production technique of the studied objects have been noted. They are too marked to be casual and seem to indicate that the pieces belong to the same tradition and were most probably produced in the same workshop. This paper discusses the alloys and technical details of the various objects. The copper-based alloys on the diverse artifacts show black, red, orange and yellow patinations. Some ancient texts, such as the recipes of the Greek Alchemists, the Papyrus of Leyden, the Papyrus of Stockholm and later translations of the Greek alchemistic texts seem to refer to the various alloys employed for the objects. The collected data certify the use of patinated alloys similar not only to shakudo, but - for the first time - also to other irogane alloys, such as sentoku and akagane, and the existence of a highly specialized workshop belonging to the Romano-Egyptian world, in which extraordinary artifacts with astonishingly complex and colourful inlays were produced.

This paper deals with the study of the layers with remains of metallurgical activities from via Moneta (IV-III century BC - I century AD). The district was located in the centre of the oppidum near the area where the Roman forum was to be built at a later stage. The remains of twenty-three metallurgical workshops were partially reconstructed. In these workshops raw iron and copper alloys were worked in order to be transformed into finished objects and accessories for forniture. The iron forges' hearts and the smelting furnaces for the copper alloys are described and reconstructed. The metal production was highly specialized: various iron items and iron sheets were made, fluxes were used for its soldering. Copper alloys were used for the production of nails, rivets, upholstery nails, thin bronze sheet was made in order to cover the heads of iron nails and possibly also La Tène fibulae of Nauheim type or of related types were made. In many workshops both iron and copper alloys were worked in order to make pieces of furniture and object made with different metals.

The smelting copper slags from the archaeological sites of Transacqua and Segonzano in Trentino (Italy) were fully analysed to study the extraction of copper from copper and iron sulphide minerals that were carried out in the southeastern Alps during the Late Bronze Age. A combined approach involving physical, chemical, mineralogical and petrographic analyses was applied on over 130 copper slags from Transacqua and Segonzano. Three different types of slags were distinguished from the mineralogical and chemical points of view, differing in the size and relative amount of the unreacted sulphides and matte, the size of metallic copper prills, the ratio between unreacted quartz and newly formed silicate phases and viscosity. By combining all the observations, it is suggested that the three types of slags are the product of a Cu-smelting process formed by three main operations: slagging, matting and refining, which were standardised in the southeast Alps between the fourteenth and the eleventh century BC.

Analysis of metal objects with portable and handheld X-ray fluorescence spectrometry has become increasingly popular in recent years. Here, methodological concerns that apply to non-destructive, surface examination with XRF instruments of ancient metal artefacts are discussed based on the comparative analyses of a set of copper-based objects by means of portable X-ray fluorescence (pXRF) and electron probe microanalyser (EPMA). The analytical investigation aims to explore issues of instrument comparability and reliability of the non-invasive pXRF results. The different analytical approaches produce a comparable pattern for the major element concentrations, but substantial variation is evident when it comes to the absolute values for major and minor/trace elements.

In the years between 2008 and 2012, as a result of a building conversion, it has been carried out a set of archaeological excavations in the western district of Chinzica, in Pisa.
Th e archaeological investigations allowed us to bring to light a complex workshop area, designed to produce and sale glassware and metal items, chronologically framed in the period between the beginning of the thirteenth century and 1406 the year that witnessed the fl orentine conquest and the consequent destruction of the workshops.
Set in the northern sector, sealed by a thick layer of iron slag, it has been identifi ed an entire shop, apt for the production and sale of copper alloy and iron items.
Th e whole organization of the craft ing process can be reconstructed thanks to the detection of smelting furnaces, forges areas, areas for workbenches and goods storage. The numerous finds -particularly those related to the clothing accessories – show off the complete manufacturing process by off ering an insight into the techniques of the copper alloy processing. Of particular interest are the many clay crucibles and fragments of clay molds for mass production that testify to a highly specialized activity that could meet high-volume production.
The exceptionality of the ceramic context found in association with the productive areas grants us the opportunity to date the techniques and tools used in metalworking, as well as allowing a thorough analysis of the socio-economic impact of pisan blacksmiths in the city's economy.

Studies concerning European Proto-historic metallic artefacts can provide important clues about technological transfers during a period of time characterised by diverse cultural interactions. A collection of Proto-historic metallic artefacts from Medronhal (western Iberian Peninsula) composed by rings, bracelets and a fibula related to different cultural affiliations were investigated by micro-EDXRF to provide a major and a minor elemental characterisation. Results show that the Medronhal collection was manufactured in a Cu-Sn alloy (binary bronze) with similar Sn contents among the various types of artefacts and a low impurity pattern. Results of the type and quality of metal were compared to other artefact collections to infer about metallurgical parallels. Strong parallels with indigenous Late Bronze Age Iberian metallurgical productions were found.

Castillejo del Bonete is a cave adapted as a funerary monument during Late Prehistory. Various well-preserved metal objects were recovered from the site, both within and outside the graves.
This paper presents a catalogue and analysis of the metal objects recovered before the end of 2012, and comprises results obteined from archaeometallurgical studies and an interpretation of their cultural and territorial context. Unpublished data from El Acequión, Albacete, is also presented to provide a comparative perspective on the provenance of metal during the Bronze Age.
The metal artefacts were archaeologically contextualized prior to analyses, wich included lead isotopes, XRF spectrometry, SEM microanalysis, metallography and microhardness analysis.
Our results reveal the use of various types of metals and the application of metallurgicall processes associated with Chalcolithic and ancient Bronze Age phases. Overall, the results obtained showed that the metal artefacts analysed did not contain tin, but high levels of arsenic, probably originating from the area of Linares (Jaén).

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Castillejo del Bonete es una cueva que fue utilizada y adaptada como monumento funerario durante la Prehistoria reciente. Abundantes piezas metálicas en óptimo estado de conservación se han recuperado de los túmulos construidos encima de la cueva, tanto en el interior de tumbas como fuera de ellas. El objetivo de este trabajo es presentar la colección metálica del yacimiento recuperada hasta finales de 2012. También el estudio arqueometalúrgico de varias de las piezas y una interpretación del conjunto en relación a su ámbito cultural y territorial. La investigación además incorpora datos inéditos de El Acequión, Albacete, para proporcionar una perspectiva comparativa sobre la procedencia del metal en la Edad del Bronce con los datos disponibles del área argárica. Las piezas metálicas son explicadas en sus respectivos contextos arqueológicos antes de ser analizadas por diferentes métodos y técnicas: isótopos de plomo, espectrometría por fluorescencia de rayos X, microscopía electrónica de barrido con microanálisis por espectrometría de dispersión de energías de rayos X, mecanografía y análisis de microdureza. Los resultados revelan tipos y procesos metalúrgicos característicos del Calcolítico y fases antiguas de la Edad del Bronce. En general son piezas sin estaño pero con alto contenido en arsénico, procedentes en buena parte del área de Linares.

The study of early metallurgy has many aspects and
has, accordingly, taken many forms and foci (Rehren
and Pernicka 2008 and literature therein). Some
scholars have documented the morpho-typological
evolution of artefact types and some have explored the
role of metals in creating social hierarchies, in storing
and displaying wealth, or the more transcendent role
of metals in a variety of rituals. Other researchers are
fascinated by the skills and technical achievements
of the metalworkers and their intangible heritage
as expressed in intricate castings, ingenious
manufacturing methods and elaborate surface
decorations. Yet others study the transformation of
rocks and ores to metal as documented in the slags
and furnace fragments or try to trace the geological
origins of metal objects, as a proxy for the movement
of people, materials, and ideas. The investigation
of ancient mining extends well beyond the field of
archaeometallurgy, with mines for flint, pigments,
precious stones and salt all pre-dating metal smelting,
and quarrying for building stone exceeding metal
mining both in scale and value generation (e.g. Schauer
et al. 2020). This range of interests inevitably implies the
application of a multitude of methods, borrowed from a
host of mother disciplines, adjusted and refined to form
the interdisciplinary field of archaeometallurgy. It also
makes any holistic project both a daunting prospect
and an exercise in interdisciplinary diplomacy.

This chapter reviews the pre-existing evidence and
interpretations for early mineral use and metallurgy in
the Balkans from the earliest use of copper minerals at
c. 6200 BC (Late Mesolithic-Early Neolithic) to c. 3700
BC (end of the Chalcolithic). It presents the empirical
and intellectual foundations upon which the data,
analyses and interpretations of The Rise of Metallurgy
in Eurasia project builds. The early metallurgy in this
region encompasses the production, distribution and
consumption of copper, gold, bronze, lead and silver, all
being either pure metals or a natural alloy (tin bronze)1.
The chapter initially defines the geographical and
temporal scope under consideration before evaluating
the archaeological and metallurgical evidence in
relation to: mineral exploitation; mining; smelting,
metals and metal artefacts; and metal circulation.
Following each of these sub-sections is a summary of
how The Rise of Metallurgy in Eurasia project oughtto
contribute to this aspect of metallurgical activity,
setting this in relation to the project’s six research
questions as presented in Chapter 2. The chapter
concludes by highlighting the dominant interpretative
narratives relating to early metallurgy, metallurgists
and societies in the Balkans that The Rise of Metallurgy
in Eurasia project will evaluate, against all the available
and relevant archaeological and metallurgical data.

JOURNAL OF HISTORICAL AND ARCHAEОLOGICAL RESEARCH, 2018, 1, 7-16.
ABSTRACT: 
During the Copper age present day Bulgarian lands are part of two wide metallogenic zones – Eastern and Western. The Eastern zone includes present day Eastern Bulgaria. The Western zone includes present day Western Bulgaria, Eastern and Southern Serbia. The Eastern zone is characterized by it’s polymetallic, „dirty”, ores, while for the Western typical are the “pure” copper minerals. The “dirty” ores can be extracted in controlled reductive environment and prolonged maintenance of constant temperature. Such conditions are not needed for the smelting of the “pure” copper ores.
In ancient times there were used two main technologies to extract the copper from the ores: 1. smelting in crucibles; 2. smelting in furnaces. However, only the “pure” copper ores can be smelted in crucibles, because they don’t release slag. Crucibles are found mostly in present day Western Bulgaria. On the other hand, furnaces suitable for “dirty”ore smelting, are known only from the eastern part of present day Bulgaria. So, it is obvious that the metallurgical technology used in modern day Western Bulgaria differs from the used in Eastern Bulgaria. Those differences probably are due to the characteristic features of the ores in which of the two metallogenic zones. In Eastern Bulgaria the “dirty” ores were preferred, while in the western part of modern Bulgarian lands the main aim of the miners were the monometallic copper minerals. On the other hand, during the early Chalcolithic in present day Eastern Serbia “dirty” ores were purposefully smelted, while during the late Chalcolithic dominates the usage of “pure” cooper minerals. This could be caused by the fact that in the late Chalcolithic the territory of modern Eastern Serbia becomes part of the Krivodol-Salcuţa-Bubani cultural phenomenon, whose roots derive from present day Western Bulgaria. So, it could be considered that the preferring of specific kinds of ores during the Chalcolithic is not subordinate only to the existing natural resources, but also to culturally distinct technological traditions.

The conference at Miskolc was the fifth of a series that begun in Milan in 2003, followed in 2007 by the conference in Aquileia, both in Italy. The third was held at Bochum, in Germany, in 2011 and the fourth at Madrid, Spain, in 2015. The special aim of our 2019 conference was that of emphasizing and strengthening the interdisciplinary character and the various activities in the field of archaeometallurgy and widening the focus towards Eastern Europe.

Metal production evidence yielded during the
excavation campaigns 2012 and 2013 in Belovode shows
similar characteristic to the samples from the site
studied and published previously (Radivojević 2012,
2013, 2015; Radivojević and Kuzmanović Cvetković
2014; Radivojević and Rehren 2016; Radivojević et al.
2010a). These are predominantly malachite mineral
and ore samples, most likely roughly beneficiated (no
samples larger than 2–3 cm in length, see Appendix
B_Ch11), and very importantly, without any significant
spatial pattern in the excavated area of Trench 18 or
its extension (T18ext henceforth). These minerals were
discovered in all areas, whether in living or economic
spaces, inside the dwellings and other features, and
across the excavation spits, which is why they have also
been found by previous excavation campaigns.

Eight copper beads from three central Namibian sites and one possible ore specimen were subjected to metallographic and chemical
analysis. The cylindrical beads were found to consist of indigenously produced copper with characteristic cuprite inclusions. The
method of fabrication was reconstructed from description of the microstructure, with initial hot working and annealing followed
by final cold work to hammer the joins closed without solder. There was significant variation in the inclusion chemistry, probably
indicating regional trade, although detailed sourcing studies would be necessary to confirm this

Previous archaeometallurgical studies on Bronze Age China mainly focused on finished artefacts, whereas our understanding of copper smelting technology of this period is still limited. This paper, for the first time, presents analytical results of metal production remains from the site of Laoniupo in Guanzhong Plain, central Shaanxi. It reveals that arsenical copper was produced at this site by smelting arsenic-rich polymetallic ores with raw copper or high purity copper ores. The identification of metal production in the Guanzhong Plain is significant for the investigation of regional development and interregional interaction of Bronze Age cultures in China. The possible exploitation of ores from deposits in the Qinling Mountain region during this period is also discussed in this article.

Previous archaeometallurgical studies on Bronze Age China mainly focused on finished artefacts, whereas our understanding of copper smelting technology of this period is still limited. This paper, for the first time, presents analytical results of metal production remains from the site of Laoniupo in Guanzhong Plain, central Shaanxi. It reveals that arsenical copper was produced at this site by smelting arsenic-rich polymetallic ores with raw copper or high purity copper ores. The identification of metal production in the Guanzhong Plain is significant for the investigation of regional development and interregional interaction of Bronze Age cultures in China. The possible exploitation of ores from deposits in the Qinling Mountain region during this period is also discussed in this article.