Fibula and Snake Bracelet from Albania. a Case Study by Om, Sem-Eds and Xrf
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View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by ZENODO SCIENTIFIC CULTURE, Vol. 2, No. 2, (2016), pp. 9-18 Copyright © 2016 SC Open Access. Printed in Greece. All Rights Reserved. DOI: 10.5281/zenodo.44895 FIBULA AND SNAKE BRACELET FROM ALBANIA. A CASE STUDY BY OM, SEM-EDS AND XRF. Olta Çakaj1, Teuta Dilo1, Gert Schmidt2, Nikolla Civici3, Frederik Stamati4 1Faculty of Natural Science, University of Tirana, Albania 2Institut für Keramik, Glas- und Baustofftechnik, TU Bergakademie Freiberg, Germany 3Centre of Applied Nuclear Physics, Albania 4Centre of Albanological Studies, Tirana, Albania Received: 20/11/2015 Accepted: 17/01/2016 Corresponding author: Olta Çakaj ([email protected]) ABSTRACT Albania is situated west of the Balkan Peninsula while Shkodra and Durrës are respectively north-western and western cities. The objects of this study are a fibula (IX-VIII BC) found in Shkodra and a snake bracelet (III-I BC) found in Durrës. The purposes of this research paper are to study the chemical composition, pro- duction technology, corrosion products, microstructure and the possible minerals used for the objects’ man- ufacture. To fulfil these tasks the objects’ samples have been analysed with μ-XRF, OM, Vickers microhard- ness tester and SEM-EDS. Both objects resulted authentic copper-tin alloys with less than 2% of lead. They have approximate microhardness values (116.2HV and 113.6HV), with corrosion products from the first and second oxidized layer. The fibula and the snake bracelet has been casted, hot and cold worked to obtain the final shape. Both objects have lead and copper-iron-sulphur inclusions which suggest the possible use of copper-iron sulphite minerals. KEYWORDS: antique bronze, microstructure, texture, OM, SEM-EDS, μ-XRF 10 Olta Çakaj et al 1. INTRODUCTION in Cyprus since early times that its name derives from this chemical element. The copper ores of Cy- This research was performed in order to study prus are hydro carbonate and sulphate such as mala- the alloy composition of two antique objects, their chite (Cu2CO3(OH)2), azurite (Cu3(CO3)2(OH)2) and distinct production technology and the possible chalcopyrite CuFeS2. (Constantinou 1982) While in mineral used as raw material. This was archived Greece the regions rich in copper ores where is through the examination of the samples’ chemical thought that objects production was supported by content, their microhardness, microstructure and its local copper deposits are Kamariza, Ilarion, Christi- inclusions or secondary phases. Another section of ana, Agia Varvara, Sounion and Lavrion. According the article covers the qualitative determination of the to the literature copper was obtained from native corrosion products which is essential to prove the copper (Cu), cuprite (Cu2O), chalcopyrite (CuFeS2), objects’ authenticity (not fake replicas) and is helpful malachite (Cu2CO3(OH)2), azurite (Cu3(CO3)2(OH)2), for the conservation process. chalcocite (Cu2S), covellite (CuS), olivenite Albania has a favourable link position between (Cu2AsO4OH), atacamite (Cu2Cl(OH)3) and tetrahe- Europe and Asia. Scodra (in Latin, today Shkodra) drite ((Cu,Fe)12Sb4S13) (figure 1a). (Marinos & Pet- on the northwest of Albania was the capital of Ardi- rascheck 1956) aei kingdom since the III century BC. While Dyrra- Few studies have been performed about Albanian chium (in Latin, today Durrës) was founded during copper based objects this last years while other Bal- the XIII - XI century BC and became one of the most kanic countries have studied nearly all their culture important port cities of the western Balkan Peninsula heritage with physical and chemical analytical (figure 1a). After the XI century BC the first iron ob- methods. Although Albania has a rich museum fund jects began to appear marking the initiation of the only a few objects have been studied so far. 122 sil- Iron Age but it took almost three centuries for this ver alloy coins from a hoard (III B.C.), minted by the new chemical element to substitute partially bronze Illyrian king Monounios and the ancient cities of in working tools and weapons. During this time Dyrrachium (Durrës) and Korkyra (Korfuz) was copper alloys were more preferable in the produc- studied with EDXRF. One coin from Dyrrachium tion of ornaments and jewellery. Later on the Hellen- (Durrës) and one of Illyrian king Monounios from istic Period was associated with the spread of Greek the III century B.C. resulted copper-silver alloys culture influences and trade exchanges during the produced with a cold-struck process after casting. expansion of the Empire founded by Alexander the (Pistofidis et al., 2006; Civici et al., 2007) Another Great. (Prendi 1977-1978; Boardman et al. 1982; coin from Dyrrachium (Durrës) of the III-II century Jacques 1995; Ceka 2000) B.C. was determined to be a copper-tin-lead alloy Most of the copper deposits from the Jurassic and produced in a similar way compared with the coins Cretaceous periods are present in the volcanogenic mentioned above. One nail from Dyrrah used in massive sulphide compositions. They are located in land (IV-III B.C.) and one from Saranda used in a Albania, Cyprus and a few in Turkey (Kure Asikoy, ship (VI-IV B.C.) resulted pure copper which were Murgul Maden, etc.) but are very rare in other coun- hot worked after being casted. (Dilo et al., 2009) A tries. (Economou-Eliopoulos et al. 2008; Hoxha 2014) necklace (VII-VI B.C.) and a belt application (VII-VI Many chemical mineralogical studies have been per- B.C) from Shkodra were casted copper-tin-lead al- formed through the years for the Albanian territo- loys while a button (VI-IV B.C) from the same region ries. The central north (Rubik) and north (Mirditë) resulted a casted copper-tin composition. (Çakaj et underground resulted rich in copper-sulphide min- al., 2014) Some weapons were studied as well such erals associated with zinc such as pyrite (FeS2) - chal- as six swords, three spearheads and a shield from copyrite (CuFeS2) - sphalerite [(Zn,Fe)S]. Later on the south-west and south-east of Albania. The shield because of the hydrothermal solutions changes and from Apollonia (Fier, south-west Albania) was a the partial oxygen pressure increments the quantity copper-tin alloy produced throught hot working af- of chalcopyrite mineral had decreased and bornite ter casting. While one sword from Erseka (south-east (Cu5FeS4) had taken its place (figure 1b). (Çina 1975, Albania), five swords of type Naue II and three 1976; Koçi 1977; Kati 1988) Two ancient and im- speardheads from Korça (south-east Albania) result- portant mines in the region are Rudna Glava of Ser- ed copper-tin alloys. (Koui et al., 2006; Çakaj et al., bia and Ai Bunar of Bulgaria. According to different 2009) Also some copper alloy sculptures from An- studies their copper mineral deposits are hydro car- tigonea have been studied for restoration and con- bonate such as azurite (Cu3(CO3)2(OH)2) and mala- servation reasons. (Budina and Stamati, 1989) chite (Cu2CO3(OH)2). (Jovanovic 1978; Gale 1990) The copper sources were so many and so important SCIENTIFIC CULTURE, Vol. 2, No 2, (2016), pp. 9-18 Fibula and snake bracelet from Albania. a case study by om, SEM-EDS and XRF 11 a) b) Figure 1. a) Political map of the Balkan Peninsula and the Near East. It shows ancient copper mines in Serbia (Rudna Glava), Bulgaria (Ai Bunar), Lavrion (Greece); copper rich regions in Cyprus and in northern Albania (Mirditë). This study objects were found in Scodra and in Dyrrachium. (http://www.worldatlas.com/webimage/countrys/europe/balkans.htm). b) The extension of FeS2-CuFeS2 and FeS2- CuFeS2-(Zn,Fe)S ores in Albania. Regions rich in copper ores (Mirditë, Rubik), objects’ excavation locations (Scodra, Dyrrachium), excavation locations of former studied objects (Shkodra, Durrës, Saranda, Apollonia, Antigonea, Erseka, Korça), the Albanian capital (Tirana). (Economou-Eliopoulos, Eliopoulos, and Chryssoulis 2008.) tion). This fibula has no visible clip on the back side 2. MATERIALS AND METHODS and its total length is approximately 2.3m. The snake Sample from the fibula and the snake bracelet bracelet (III-I BC. Hellenistic Period, object no. 60205, was removed using a small pincers and in both cases code 029, file no. 9786) comes from the Hellenistic it didn’t exceed 6mm3 in volume (Figure 2a). The Period, has a diameter of 0.047m, the height of spi- sampling process was carefully carried out in order rals is 0.032m and the total length is 0.7m. The cross to have almost no impact on the object integrity and section of the fibula is 3.2∙10-6m2 and the one of the to collect as much information as possible. The fibula snake bracelet is 4∙10-6m2. Both objects have no visi- (IX-VIII BC Iron Age, object no. 17960, code 015, file ble defects and the cross section is approximately the no. 485) dates back to the Iron Age and has a spiral same along the whole length. (Prendi 1958, 2008) string that forms two round discs 0.065m in diameter Figure 2a) shows the objects’ photos while 2b) shows connected together (0.145m length from one side to their sketches. the other) while each disc has a conical button on the centre (the two discs found separated in the excava- a) b) Figure 2. a) Photos of the fibula (left), the snake bracelet (right) along with the positions where each sample was taken, b) the corresponding objects’ sketches. The examine procedure starts with µ-X ray paper (30μm, 18μm, 5μm) and cloth with diamond fluorescence (µ-XRF) performed on 2-3 spots of the paste (3μm, 1μm)associated with DP-Lubricant Blue.