Bronze Artifacts Research Articles

The role of surface analysis in the strategies for conservation of metallic artefacts from the Mediterranean Basin

Conservation and valorization of cultural heritage is a fundamental element and an essential mission of the Mediterranean countries where most of the ancient and fascinating witnesses of human art and creativity are conserved. A large component of this cultural heritage consists of material cultural assets that are often exposed to harmful long‐term effects of environmental pollution, inappropriate handling, and intrinsic chemical–physical instability. Many risks can be mitigated, provided that there is a proper knowledge of the materials involved and of their degradation processes and adequate means to counteract these processes or to restore the materials. The employment of surface analysis can be extremely useful for the development of both tailored conservation procedures and methodologies as a function of the different degradation mechanisms that affect the artefacts, as well as for the monitoring of the conservation state and the identification of the manufacturing techniques. Several metallic artefacts coming from different archaeological sites of the Mediterranean Basin have been examined: weapons found during the excavation of the Ayanis fortress of the Urartu civilization (Lake Van, Anatolia, Turkey) and silver and bronze artefacts found at Tharros (Italy), a Phoenician–Carthaginian and then Roman city located along the Sardinian coast. They have been studied by means of the combined use of selected area X‐ray photoelectron spectroscopy, X‐ray diffraction, optical microscopy, and scanning electron microscopy + energy dispersive spectrometry. The surface analysis techniques are able to give important contributions in the identification of chloride ions that may dramatically affect the chemical–physical stability of the copper‐based artefacts, thus allowing developing proper conservation strategies, as well as in the identification of the presence of mercury on gilded artefacts, thus giving information on the manufacturing technique. Copyright © 2014 John Wiley & Sons, Ltd.

Depth-dependent calibration for quantitative elemental depth profiling of copper alloys using laser-induced plasma spectroscopy

This work presents new calibration procedures for deep elemental depth profile analysis of bronze artifacts. A simple ablation model is developed for the estimation of the ablation rate and hence for deriving the depth spatial calibration scale. Elemental quantification is obtained through the construction of calibration surfaces, using reference samples of known composition, relating laser-induced plasma spectroscopy (LIPS) intensity ratios, content of atomic species and number of laser pulses. Such a method represents a refinement of the standard LIPS quantification approach based on calibration curves, which is extended here to the generation of significantly deep craters into the material under investigation up to several hundred microns. The depth dependence of the calibration surfaces measured is discussed in the framework of a simplified model of depth-dependent plasma temperature.

Virtues of Giambologna from Grimaldi Chapel Archaeometrical Characterization

This scientific investigation on metal artwork is meant to expand knowledge regarding the technical skills developed by artists in sculpture manufacturing. Moreover all the gathered data support the speculation about the motivations behind the choices of certain material or a specific manufacturing method (e.g., economic or technical reasons, or both). The subject of this study is the Virtues sculptural group made at the end of the XVI century by Giambologna to decorate the Grimaldi Chapel in the church of San Francesco di Castelletto (Genoa, Italy). Six life-size statues depicting Charity, Justice, Hope, Fortitude, Faith, and Temperance (i.e., the artwork discussed in this article); seven bas-reliefs; and six winged representations of putti are what remains of the original monumental project. X-ray fluorescence, a nondestructive investigation method, was applied to determine the chemical nature of the metallic substrate and of the “artistic” and natural patinas. The achieved results allowed for distinguishing variations in the content of the major alloying elements that might correspond to a motivated will of the artist connected to technical and aesthetic aims: the production of defect-free and golden bronze artifacts.

Electrochemical characterization of bronze historical objects using voltammetry of microparticles

This work presents the application of voltammetry of microparticles (VMP) to the characterization of metallic artefacts. The paper illustrates the principle of the technique and the methods for the identification of metals and copper minerals. VMP can be considered a non-invasive technique as it requires a minimum amount of material for performing the analyses. To emphasize the efficacy of this technique regarding characterization of cultural heritage materials, two bronze artefacts of different historical periods were investigated. By using a paraffin-impregnated graphite electrode, the composition of the alloy and the copper minerals present in their patinas were analysed and identified. The results obtained from the electrochemical characterization were confirmed by complementary analysis carried out with X-ray fluorescence and X-ray diffraction.

Analysis of the Quintilii’s Villa Bronzes by Spectroscopy Techniques

The aim of this work is the characterization, with different diagnostic tests, of three fragments of bronze artefacts recovered from the Villa of the Quintilii (located in the south of Rome). In particular, the sample alloys were investigated by different chemical and morphological analysis. Firstly, an analysis of the alloy, implemented through the electronic spectroscopy, was taken to discriminate the bronze morphology and its elemental composition. Subsequently, a surface analysis was realized by molecular spectroscopy to identify the alteration patinas on surfaces (such as bronze disease). Two diagnostic techniques are used for the alloy analysis: scanning electron microscopy (SEM) connected to the EDX spectroscopy (to study the morphology and alloy composition) and Auger electron spectroscopy (AES) (to identify the oxidation state of each element). Moreover, for the study of surface patinas, IR and Raman spectroscopies were implemented. All studies were performed on the “as received” samples, covered by a thin layer of excavated soil and on samples processed in an aqueous solution of sulphuric acid (10%), to remove patinas and alterations.

Wrestling Magic: National Wrestling in Buryatia, Mongolia and Tuva in the Past and Today

This article presents the historic development of national wrestling styles in three neighbouring Inner Asian countries. In all of them wrestling has been and still is the most popular athletic competitive activity. First, an overview of the general geographic features and history of the area is given. Second, the article outlines the origins of wrestling in these countries. It is shown that wrestling basically has its origins in magic cults with additional roots in hunting and warfare. Evidence for these origins provides ancient petroglyphs, bronze artefacts, myths, folk literature, ancient ritual practices, historiographic literature, ethnographic reports and the rules of the competitions itself. The third part of the article describes how wrestling competitions were functionalised for various purposes – magic, social, military and political – through the course of history. The last part focuses on the post-Soviet period, in which national wrestling has been flourishing in all three countries. In this period, wrestling has been re-traditionalised and utilised for new state cults as well as – to varying extents – for Buddhist ritual purposes. The article shows that general socio-economic developments ongoing in these societies were always clearly reflected by the wrestling competitions as well as by the wrestlers' behaviours themselves.

Diamond-like carbon coatings for the protection of metallic artefacts: effect on the aesthetic appearance

Plasma-enhanced chemical vapour deposition (PECVD) is an environmentally friendly process used to deposit a variety of nano-structured coatings for the protection or the surface modification of metallic artefacts like the SiO2-like films that have been successfully tested on ancient silver, bronze and iron artefacts as barriers against aggressive agents. This paper deals with the preliminary results of a wider investigation aimed to the development of eco-sustainable coatings for the protection of Cu and Ag-based artefacts of archaeological and historic interest. Diamond-like carbon (DLC) coatings have been deposited by PECVD in different experimental conditions, in a capacitively coupled asymmetric plasma reactor, placing the substrates either on electrically powered electrode (cathodic mode) or grounded electrode (anodic mode) with and without hydrogen addition in the gas mixture. The final goal is to develop a coating with good protective effectiveness against aggressive atmospheres and contemporarily with negligible effects on the aesthetic appearance of the artefacts. The evaluation of possible colour changes of the surface patinas, due to coating process, was performed by optical microscopy and colorimetric measurements. Furthermore, to evaluate the reversibility of the thin DLC layer, an etching treatment in oxygen plasma has been successfully carried out and optimized. The chemical-physical characterization of the deposited DLC coatings was performed by means of the combined use of micro-Raman and XPS spectroscopies. The results show that the DLC films obtained in the anodic mode, may be proposed as a viable alternative to polymeric coatings for the protection of metallic ancient objects.

Tainted ores and the rise of tin bronzes in Eurasia,c. 6500 years ago

The earliest tin bronze artefacts in Eurasia are generally believed to have appeared in the Near East in the early third millennium BC. Here we present tin bronze artefacts that occur far from the Near East, and in a significantly earlier period. Excavations at Pločnik, a Vinča culture site in Serbia, recovered a piece of tin bronze foil from an occupation layer dated to the mid fifth millennium BC. The discovery prompted a reassessment of 14 insufficiently contextualised early tin bronze artefacts from the Balkans. They too were found to derive from the smelting of copper-tin ores. These tin bronzes extend the record of bronze making byc. 1500 years, and challenge the conventional narrative of Eurasian metallurgical development.

Chinese archaeological artefacts: Microstructure and corrosion behaviour of high-leaded bronzes

Metallographic features of ancient bronze artefacts often hide peculiar micro-chemical processes and corrosion behaviours, which are worth to be studied as they can provide conservators and archaeologists with valuable tools and information. It is widely documented that Chinese bronzes were cast and the way to adjust their properties was to change the alloy composition. In particular, addition of lead, which is insoluble in the bronze matrix, results in the formation of inclusions or globules, which undergo oxidation processes leading to their conversion into corrosion products. The mechanisms through which this occurs were still poorly investigated. The present work was conducted to further study the corrosion behaviour of high-leaded bronze, especially focusing on the behaviour of lead globules. To this aim, a collection of Chinese archaeological bronzes, showing intermediate steps of degradation, were selected and investigated. The use of combined microscopy-based, molecular and elemental, analytical techniques allowed the characterization as well as the precise location of corrosion products, thus enabling us to propose a degradation pathway basing on thermodynamic data provided by Pourbaix diagram. The achieved results will be useful for researchers involved in these kinds of studies to better interpret data obtained.

A microstructural characterization of some Late Bronze Age metals from Fraga dos Corvos site: fibula, pendants, riveted sheet and droplet

The knowledge of our pre-history and ancient metal artefacts production methods can only be deeply investigated through the multidisciplinary approaches involving different analytical techniques including microscopy techniques. The present study concerns the elemental and microstructural characterization of pre-historic bronze artefacts from the Northwestern Iberia Peninsula. During Bronze Age an increment of metal artefacts production and its typological diversification is observed related to the development of metallurgical technology. Several artefacts have been found during recent excavations at the Bronze Age settlement of Fraga dos Corvos (Macedo de Cavaleiros, Portugal). The analysis of metallurgical remains points out to the existence of local metallurgical activities. Five bronze artefacts previously analysed by micro-EDXRF, an Acebuchal fibula fragment, two pendants and a riveted sheet (probably a fragment of a vessel or cauldron) with average concentration values of 10±1.1% Sn and ~2±0.5% Pb and a droplet (?) with ~5% Sn and ~4% Pb, were selected for optical microscopy (OM) and SEM-EDS analysis.Microscopy observations showed to be very important for the comprehension of pre-historic bronze metallurgy, allowing the identification of different phases, inclusions and thermomechanical processes applied during artefacts production. The fibula and the pendants show an equiaxed and twinned microstructure with slip bands (Figure 1 (a) and (c)). The characteristics observed are related to recrystallized and plastically deformed α-Cu structures. These features indicate that the artefacts were hammered and annealed (thermomechanical cycling), ending with a hammering operation. The pendants only exhibit slip bands near the surface, probably resulting from a finishing operation. Lead and Cu-S inclusions are frequently observed. The riveted sheet has an annealed microstructure with large α-Cu grains, undissolved (α+δ) eutectoid and few annealing twins. Elongated Cu-S inclusions, lead globules and pores were identified by SEM-EDS (Figure 1 (a)). Its microstructure indicates that shaping was obtained by just one or few thermomechanical cycles. The droplet presents a coarse and cored dendritic structure (Figure 1 (b)). Rounded Cu-S inclusions, lead globules and pores were also observed. Those are characteristics of a slow cooled as-cast alloy. Due to its low Sn content the (α+δ) eutectoid is absent. As a final note, microscopy techniques allowed establishing the manufacture processes involved in bronze metallurgy and to conclude that different thermomechanical processes were applied according to the typology of the artefact.Financial support received from the Portuguese Science and Technology foundation under the EarlyMetal project PTDC/HIS-ARQ/110442/2008 and the grants SFRH/BPD/73245/2010 (EF) and SFRH/BD/72369/2010 (EL). Financial support of CENIMAT/I3N through the Strategic Project LA25/2011-2012 (PEst-C/CTM/LA0025/2011) is gratefully acknowledged.

Microstructural characterisation of a collection of Protohistoric bronzes

Microstructural characterisation of an archaeological collection of Protohistoric bronze artefacts attributed to around the VIII century B.C. and has been carried out using optical microscopy (OM) and scanning electron microscopy combined with energy dispersive spectroscopy (SEM-EDS). The collection was found in Medronhal cave (Condeixa-a-Nova, Portugal) and is composed by 1 fibula, 5 bracelets and 31 rings.Small areas on the surfaces of the artefacts were cleaned from corrosion and were metallographically prepared by a manual polishing with several diamond suspensions in a cotton swab until 1 micron diamond size. OM observations were performed in bright field (BF) illumination and under polarized light (Pol), in unetched and etched conditions. SEM-EDS was performed without a conductive coating for a minimum external elemental interference.OM observations allowed the study of the method and sequence of manufacture involved in the production of the various types of artefacts. Results show that the fibula and the bracelets have equiaxed (recrystallised) grain structures resulting from cyclic thermo-mechanical treatments performed to a pre-form cast bar until requested shape and surface finishing was attained. The rings, which are of diverse sizes, have various types of microstructures as a result of diverse manufacturing techniques. Some show a dendritic structure that resulted from the casting, and others show recrystallised structures that resulted from cycles of deformation and annealing procedures posterior to their casting (Figure 1).SEM-EDS analysis allowed the study of the presence of inclusions in the metallic matrix and the study of corrosion in some artefacts (Figure 2). Different types of inclusions were identified, namely copper sulphides, tin oxide, and lead rich inclusions. Both copper sulphides and lead inclusions are commonly found in archaeological bronzes, and can be a result of copper ores impurities. Tin oxide, on the other hand, is not so common, and its presence can be understood as a result of preferential oxidation of tin regarding copper during a melting or alloying operation. The study of the interface alloy/corrosion showed the presence of chlorides in internal corrosion layers, which can probably be related to an aggressiveness of the burial environment.This research work has been financed by the Portuguese Science Foundation (FCT) through the EarlyMetal project (PTDC/HIS-ARQ/110442/2008), the grant SFRH/BPD/73245/2010 (to EF) and the Strategic Project-LA25-2011-2012 (PEst-C/CTM/LA0025/2011) (to CENIMAT/I3N).

Egyptian Blue cakes from the Ayanis fortress (Eastern Anatolia, Turkey): micro-chemical and -structural investigations for the identification of manufacturing process and provenance

The microstructure and chemical composition of blue cakes, found during the archaeological excavation of the Ayanis fortress (Eastern Anatolia, Turkey), have been investigated by means of scanning electron microscopy combined with energy dispersive spectrometry (SEM–EDS), X-ray diffraction (XRD), micro-Raman (μ-Raman) and optical microscopy (OM) techniques. The analysis of the Ayanis cakes has shown the presence of Egyptian blue (i.e. CuCaOSi4O10, cuprorivaite), as the major component, intermixed with minor amount of other phases such as partially reacted quartz grains, an adherent glass phase and copper oxides. Since the finding of Egyptian Blue in Turkey has been never reported so far, great attention has been paid to its characterisation. The micro-chemical and micro-structural investigations of the Ayanis cakes have allowed a further insight into the manufacturing process and into the sources of the starting materials. The results of the characterisation have revealed some significant differences with respect to Egyptian blue cakes found in Egypt and Mesopotamia, as for instance the absence of tin excluded the use of bronze scraps or filings in their preparation differently from those produced in Egypt and Mesopotamia. Furthermore, some peculiarities of Egyptian blue found in Ayanis, as the detection of zinc in the cakes, allow to put forward the hypothesis of a local production considering that a large part of the bronze artefacts found at the Ayanis fortress is characterised by the presence of zinc as minor alloying element.

New insights into early bronze age damascene technique north of the alps

Damascening, defined in this context as the inlay of one metal into a different metal base, is a rare decorative technique in the Early Bronze Age, known only from seven bronze artefacts found north of the Alps. This paper reports on the first thorough scientific examination of one such find, the axe from Thun-Renzenbühl grave no. 1. This interdisciplinary project involving several institutions in Germany and Switzerland investigated the axe by means of neutron radiographic imaging and X-ray microprobe methods, supported by microscopic examination. The result is an attempt to reconstruct the fabrication and decoration process and to reconsider the enigmatic question of the origins of the damascene technique north of the Alps.

Unusual surface degradation products grown on archaeological bronze artefacts

Within the framework of the EFESTUS project funded by the European Commission a large number of Cu-based archaeological artefacts from the Mediterranean basin have been studied to investigate their chemical composition, metallurgical features and corrosion products nature (i.e. the patina). By means of the combined use of X-ray photoelectron spectroscopy (XPS), optical microscopy (OM), scanning electron microscopy with energy dispersive X-ray spectrometry (SEM-EDS) and X-ray diffraction (XRD) the bronze artefacts have been studied for the detailed identification of the corrosion products and their micro-chemical structure in order to achieve information about degradation agents and mechanisms. In the present work, some examples of unusual corrosion products formed on the objects during the long-term burial are presented and related to the peculiar local context revealing the strong interaction between the bronze artefact and the chemical components found in the archaeological site.

Micro-chemical and micro-structural investigation of archaeological bronze weapons from the Ayanis fortress (lake Van, Eastern Anatolia, Turkey)

Bronze weapons (VII cen BC) found during the archaeological excavation of the Ayanis fortress (lake Van, eastern Anatolia, Turkey) are investigated in order to determine their chemical composition and metallurgical features as well as to identify the micro-chemical and micro-structural nature of the corrosion products grown during long-term burial. Small fragments were sampled from the artefacts and analysed by means of the combined use of optical microscopy (OM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS). The results show that the bronze artefacts have been manufactured by using alloys with a controlled and refined chemical composition demonstrating the high level metallurgical competence and skill of the Urartian craftsmen and artists. Furthermore, the micro-structural and metallurgical investigations evidence the presence of equiaxed grains in the matrix, indicating that the artefact were produced by repeated cycles of mechanical shaping and thermal annealing treatments to restore the alloy ductility. From the degradation point of view, the results show the structures and the chemical composition of the stratified corrosion layers (i.e. the patina) where the copper or tin depletion phenomenon is commonly observed with the surface enrichment of some elements coming from the burial soil, mainly Cl, which is related to the high concentration of chlorides in the Ayanis soil. The results reveal also that another source of degradation is the inter-granular corrosion phenomenon likely increased by the metallurgical features of the alloys caused by the high temperature manufacturing process that induces crystallisation and segregation phenomena along the grain boundaries.

Evaluation of the inhibitive effect of benzotriazole on archeological bronze in acidic medium

An archaeological bronze artefact was a Punic coin excavated from the north east of Tunisia in 2001. The composition of the copper alloy revealed a content of 3.5 % of tin and 1.4 % of lead with the presence of some sulphur heterogeneity. The surface presents some roughnesses and cracks and is covered by a corrosion layer of 20–40 μm thickness. The use of benzotriazole (BTA) as an inhibitor has become a standard element for the preservation of cuprous-based metals. In order to investigate the behaviour of BTA in an acidic medium, an Electrochemical Impedance Spectroscopy (EIS) investigation was performed to characterize the electrochemical behaviour of the interface of the archaeological bronze sample/acidic medium without and with BTA addition. Impedance diagrams obtained at different immersion times show that the presence of the inhibitor prevents the diffusional process observed in the absence of BTA. The inhibition of the pre-polarized bronze surface revealed that the mechanism of action of the benzotriazole molecule in an acidic medium is governed by the chemisorption process.

Micro-stratigraphical investigation on corrosion layers in ancient Bronze artefacts by scanning electron microscopy energy dispersive spectrometry and optical microscopy

BackgroundArchaeological metallic artefacts buried in soils deteriorate by means of various environmental as well as internal factors and mechanisms over time such as change in composition and microstructure of metal and corrosive factors due to long-term burial environment. Corrosion in metals occurs in different morphologies and results in different types of corrosion products based on soil composition. Identification of corrosion mechanisms and morphology in archaeological metals can help conservators to characterize deterioration occurred in metals and make decisions to protect artefacts about preventing further deterioration. In archaeological bronzes, different layers may form on the surface of artefacts and their composition, depth and shape depends on factors noted above.ResultsIn this paper, results of investigation carried out on ancient bronzes discovered from Haft Tappeh archaeological site, southwestern Iran, are presented. The ancient bronze samples are dated to the Middle Elamite period about 14th century BC. Some of the Haft Tappeh bronze artefacts corroded completely and a multilayer structure has formed. To study the stratigraphy of corrosion layers and their composition, some bronze artefacts have been analyzed using SEM-EDS (Scanning Electron Microscopy Energy Dispersive Spectrometry) and Optical Microscopy analyses. The results show difference between the amount of Cu and Sn in layers that may follow from copper leaching from inner layers and formation of copper trihydroxychlorides because of bronze disease.ConclusionsBased on the results, it can be concluded that SEM-EDS analysis and Microscopy observations can help to characterize compositional difference between corrosion layers in the micro scale as well as corrosion mechanisms occurring in archaeological metal artefacts.

Kurhany z epoki brązu nad górnym Dniestrem – polsko-ukraińskie projekty badawcze

This paper discuses the excavations in the cemetery of the Komarów culture of the Bronze Age in Bukivna upon the upper Dniester. They have been carried out by the Polish-Ukrainian archaeological expedition as a part of the project of the National Centre of Sciences, the aim of which has been to provide comprehensive bioarchaeological characteristic and socio-cultural interpretation of the cemetery.During the field walking over 50 barrows were documented, round or slightly oval in plan. They occurred in three main clusters, arranged in groups-lines, on the watershed between the Dniester and its little, nameless tributary.The article presents the results of the study of barrow 1, in which there were discovered six features and over 400 artefacts, including 38 vessels in several deposits, 262 flint implements, fragments of structural daub, and bronze items - a pin and pendant, as well as small, burned bones.Among the features two charred wooden structures seem special and one stone-and-wood (cenotaph). Bones were “scattered” mainly between wooden structures.A series of analyses and specialist expertises had been done: radiocarbon, paleopedological, geomorphological, paleobotanical, physico-chemical. The sum of probability distribution of calibrated radiocarbon dates suggests second quarter of the second millennium BC. These dates are consistent with the analysis of the stylistics of vessels and bronze artefacts, indicating the early and classic stages of development of the Komarów culture.

Neutron Imaging of Archaeological Bronzes at the Oak Ridge National Laboratory

This article presents the initial results of 2-D and 3-D neutron imaging of bronze artifacts using the CG-1D prototype beamline at the High Flux Isotope Reactor (HFIR) located at the Oak Ridge National Laboratory (ORNL). Neutron imaging is a non-destructive technique capable of producing unprecedented three-dimensional information on archaeomaterials, including qualitative, quantitative, and visual data on impurities, composition change, voids, and structure at macro-scale levels. The initial results presented in this publication highlight how information from neutron imaging can provide otherwise inaccessible details about the methods and materials that ancient craftspeople used in creating bronze objects.

LATE BRONZE AGE BONE CRAFTING IN THE EASTERN BALTIC: STANDARDIZATION OF ARTEFACT TYPES AND INDIVIDUAL INGENUITY

Introduction The Late Bronze Age (about 1300/1100-500 BC) was the time when fortified settlements first appeared as part of the settlement pattern in the eastern Baltic region (Fig. 1). At many of these settlements no traces of significant fortifications have been discovered, but in such cases they have been built in places with natural defensive qualities (Lang 2007a, 55 ff.; 2007b, 39 ff.). The oldest fortified settlements in the Baltic countries come from Lithuania, where they were already established in the last quarter of the 2nd millennium BC; in Latvia they appeared at the end of the 2nd millennium BC (Lang 2007a, 67). The fortified settlements in Estonia date to the first half of the 1st millennium BC (op. cit., 57 ff.). Fortified settlements are indicators of important social and economic changes that took place in the eastern Baltic region at that time. They were centres of authority, as well as of trade and crafts, and played an important role in the organization of bronze circulation (Lang 2007b, 77 ff.). The most important craft was probably bronze casting, witnessed by numerous clay moulds and their fragments found at such settlements (Vasks 1994, pl. XV, XVI; Grigalaviciene 1995, 102 ff.; Sperling 2006, 37 ff.; 2011, 90 ff.). Pottery-making was also of great importance, lots of fragments of both coarse-grained and fine-grained ceramic vessels have been found (Vasks 1994, pl. XVIII ff.; Grigalaviciene 1995, 202 ff., figs 117 ff.; Sperling 2006, 42 ff.; 2011, 157 ff.; Lang 2007a, 125 ff., fgs 58 ff.). [FIGURE 1 OMITTED] Bone and antler artefacts constitute the most numerous find group after ceramic vessels and clay moulds. The large number of bone and antler artefacts among the finds from the Bronze Age sites demonstrates the importance of bone and antler as raw materials in the society of the period. Although simple ad hoc tools are represented among them, a certain standardization of selected material and shape is characteristic of many bone tool types in the period under discussion. Such artefact types were e.g. bone arrow- and spearheads, harpoon heads and hoes or ard points made of antler, awls of goat/sheep metapodials, antler spoons and handles (e.g. Luik & Maldre 2007; Luik 2011; 2013; Luik et al. 2011). Such standardization probably reflects some degree of organization and control in bone and antler-working. Some foreign bronze artefacts have been replicated in more easily available local materials--bone and antler. For example double buttons imitating Scandinavian bronze double buttons and tutuli were made from antler (Luik & Ots 2007). Bone has been used to make decorative pins in shapes resembling bronze specimens spread across Scandinavia and central Europe. Some of these imitations are carved very skilfully, requiring certain skills and experience from their producer (Lang & Luik in print). People never copy things blindly; copying often involves the idea that the copy gains some power from the thing copied (Hodder 2012, 123). Imitations made in other substances have been regarded as characteristic of periods when important social changes took place in the society (Choyke 2008). Presumably a new social rank arose whose needs such replicated artefacts met and therefore craftspeople with necessary skills were also needed (Luik 2007). But sometimes an ancient craftsman tried to make local standardized artefacts from some other available substance. The aim of the article is to discuss some exceptional finds among Late Bronze Age bone and antler artefacts in the eastern Baltic region and to seek an answer to the question of why artisans chose different raw materials. Standardized artefact, unusual material Three case studies from the fortified settlement sites in the eastern Baltic region are presented where an artefact that usually has a very standardized shape and material was made from another skeletal element for some reason or other. …