The Production and Circulation of Carthaginian Glass Under the Rule of the Romans and the Vandals (Fourth to Sixth Century ad): A Chemical Investigation

Fifty‐seven glass samples from Carthage dating to the fourth to sixth century ad were analysed using the electron microprobe. The results show that these samples are all soda–lime–silica glass. Their MgO and K₂O values, which are below 1.5%, suggest that they were made from natron, a flux that was widely used during the Roman period. The major and minor elements show that these samples can be divided into four groups, three of which correspond to the late Roman period glass groups that were found throughout the Roman Empire: Levantine I, and ‘weak’ and ‘strong’ HIMT. Of particular interest is our Group 2, which is technologically and compositionally similar to HIMT glass and the CaO and Al₂O₃ values of which are similar to those of Levantine I. Glass of similar composition has been reported by several authors and is predominantly found dating from the late fifth to seventh century. This could represent a ‘new’ glass group; therefore further study is needed to determine its origin. Also, this study suggests that the Vandal invasion in North Africa did not disrupt the glass trade between Carthage and the Levantine coast.     

The composition of ‘naturally coloured’ late Roman vessel glass from Britain and the implications for models of glass production and supply

Naturally coloured, blue or green are the most common glass colours found in assemblages from the Roman world from the end of the 1st century BC onwards. In the 4th century two different compositions have come to dominate this group, ‘HIMT’ and ‘Levantine 1’ glasses, both of which are now thought to have been produced in the eastern Mediterranean. Using Romano-British glass assemblages from the 4th and 5th centuries, it is shown here that although the two naturally coloured glass types predominate, by far the most common composition in British assemblages is HIMT, although older, earlier blue-green compositions are still present. The earliest date HIMT could be identified in these assemblages is around AD 330, although two distinct compositions can be identified within this group which relate to changes in composition over time. A similar change over time is seen in the Levantine 1 glasses. The reasons for these patterns within the assemblages are explored within the archaeological evidence currently available for glass production and consumption in the Roman world.     

Considering the effects of the Byzantine–Islamic transition: Umayyad glass tesserae and vessels from the <Emphasis Type="Italic">qasr</Emphasis> of Khirbet al-Mafjar (Jericho,Palestine)

The paper reports and discusses data obtained by archaeological and archaeometric studies of glass vessels and tesserae from the qasr of Khirbet al-Mafjar (near Jericho, Palestine). Archaeological contextualisation of the site and chrono-typological study of glass vessels were associated to EPMA and LA–ICP–MS analyses, performed to characterise the composition of the glassy matrix (major and minor components as well as trace elements). Analyses allowed achieving meaningful and intriguing results, which gain insights into the production and consumption of glass vessels and tesserae in the near East during the Umayyad period (seventh–eighth centuries). Within the analysed samples, both an Egyptian and a Levantine manufacture have been identified: such data provide evidence of a double supply of glass from Egypt and the Syro-Palestinian coast in the Umayyad period occurring not only in the glassware manufacture but also in the production of base glass intended to be used in the manufacture of mosaic tesserae. Thus, the achieved results represent the first material evidence of a non-exclusive gathering of glass tesserae from Byzantium and the Byzantines in the manufacture of early Islamic mosaics.     

Chemical composition characterization of ancient glass finds from <Emphasis Type="Italic">Troesmis</Emphasis>—Turcoaia,Romania

This paper reports and discusses the chemical composition of 20 glass fragments discovered during the 2012 archeological survey at Troesmis (Turcoaia, Tulcea county, Romania) and dated to the Roman and the Byzantine/Early Medieval periods. The data were obtained by two external Ion beam analysis (IBA) methods—namely Particle-induced X-ray emission (PIXE) and Particle-induced gamma-ray emission (PIGE)—and they were compared to the recognized compositional glass groups from the Mediterranean region during the first millennium AD. The Troesmis assemblage turned out to contain samples belonging to several distinct categories of ancient glass, obtained from different raw materials and manufacturing procedures. Some of the analyzed vitreous finds from Troesmis were the result of glass recycling, while others were identified as deriving from Roman glass vessels imported from the Levantine or Egyptian shores of the Mediterranean. This archeometric study brings additional arguments for the long-range commercial exchanges during the Roman period.     

The Analysis of Late Bronze Age Glass from Nuzi and the Question of the Origin of Glass‐Making

This paper re‐analyses a considerable corpus of glass from the Late Bronze Age site of Nuzi, found near Kirkuk in Iraq. SEM–WDS and Sr and Nd isotopic analysis were applied, in addition to cataloguing the glass. The work showed that the glass technology at Nuzi was subtly different from contemporary Egyptian sites, using different ways of opacifying and working glass. At least two, perhaps three, Near Eastern production sites are postulated. The range of glass colours and the skill of their application at Nuzi was perhaps not on a par with the Egyptian sites. This led to a reconsideration and review of the accepted wisdom that the Near East is the source of the innovation that is glass‐making. This opinion is based on limited textual and iconographic sources and is dominated by an erroneous early date for a very developed Nuzi glass industry along with a few finds of glass vessels in early contexts. Some of this evidence has now been at least questioned, suggesting that glass‐making in Egypt, at least as early as the middle of the 15th century bc , and probably earlier, is no later than that in the Near East. It is argued that it is far from clear that the Near East was the source of the innovation and that a more cautious approach would better fit the evidence.     

THE COMPOSITION AND MANUFACTURE OF EARLY MEDIEVAL COLOURED WINDOW GLASS FROM SION (VALAIS,SWITZERLAND)—A ROMAN GLASS‐MAKING TRADITION OR INNOVATIVE CRAFTSMANSHIP?*

Archaeological excavations between 1984 and 2001 at the early Christian cemetery church in Sion, Sous‐le‐Scex (Rhône Valley, Switzerland), brought to light more than 400 pieces of coloured window glass dating from the fifth or sixth centuries ad . The aims of this paper are threefold: first, to characterize the shape, colour and chemical composition of the glass; secondly, to understand whether the production of the coloured window panes followed traditional Roman glazing techniques or was of a more innovative nature; and, thirdly, to provide some indications as to the overall design of these early ornamental glass windows. Forty samples of coloured glass have been analysed by wavelength‐dispersive X‐ray fluorescence. The results of the chemical and the technological studies showed that most of the glass was produced using recycled glass, particularly as a colouring agent. Some of the glass was made of essentially unmodified glass of the Levantine I type. The results taken together seem to confirm that raw glass from this region was widely traded and used between the fourth and seventh centuries ad . The artisans at Sion were apparently still making use of the highly developed techniques of Roman glass production. The colour spectrum, manufacture and design of the windows, however, suggest that they represent early examples of ornamental coloured glass windows.     

XRF analysis of glass beads from the Mycenaean palace of Nestor at Pylos,Peloponnesus, Greece: new insight into the LBA glass trade

In recent years there has been a growing interest in Mycenaean glass among archaeologists and scientists. Scholars have traditionally thought that all Mycenaean glass was imported either in finished form or as ingots and simply shaped or worked at the Mycenaean sites. Chemical studies of other Mycenaean glass (50 and 43) support the hypothesis that glass was imported into Mycenaean Greece, but there is also indication for glass production in mainland Greece at the palace of Thebes (Nikita and Henderson, 2006). There is no evidence for glass making or working at the Palace of Pylos, yet there is an abundance of glass beads there. The aim of this paper is to identify the technology and source for the glass of these beads and thus to ascertain how Pylos was connected to the broader Mycenaean and Mediterranean economies. The composition of the glasses was determined by means of portable XRF analysis and compared to that of other Late Bronze Age glasses from Egypt, Mesopotamia and mainland Greece. Four blue beads coloured with cobalt and one blue bead coloured with copper have Ti and Zr compositions consistent with an Egyptian origin of manufacture while five other beads show Ti and Zr concentrations consistent with a Mesopotamian origin (Shortland et al., 2007). Based on the dearth of Egyptian and Mesopotamian imports in Pylos, the presented data support the hypothesis that Pylos was receiving via internal Greek trade routes foreign-produced glass, which may have been worked abroad or in Greece.     

Glassmaking using natron from el-Barnugi (Egypt); Pliny and the Roman glass industry

Pliny the Elder describes the discovery of a process for making natron glass, which was widely used for much of the first millennium bc and ad. His account of glassmaking with natron has since been corroborated by analyses of archaeological glass and the discovery of large-scale glass production sites where natron glass was made and then exported. Analyses of Egyptian natron have shown it to be a complex mixture of different sodium compounds, and previous experiments to make glass with Egyptian natron have been unsuccessful. Here, natron from el-Barnugi in the Egyptian Nile delta, a site which also probably supplied Roman glassmakers, is used to produce glass. The experiments show that high-quality glass, free of unreacted batch or bubbles, could have been produced from natron in its unprocessed form in a single stage, that larger quantities of natron would be required than has previously been anticipated, that the presence of different sodium-containing compounds in the deposit aided melting, and that negligible waste is produced. The implications for the identification of glass production sites, for the organisation of trade and for the supply of natron within and outside Egypt are discussed in the light of Pliny’s accounts.     

Change in chemical composition of early Islamic glass excavated in Raya,Sinai Peninsula,Egypt: on-site analyses using a portable X-ray fluorescence spectrometer

The Raya port (eighth to 12th centuries) on the Sinai Peninsula, Egypt, was one of the important port cities for the Red Sea trade. We performed on-site analyses of Islamic glass vessels (used in eighth to 11th centuries) mainly from this site in Egypt using a portable XRF spectrometer. The aim of this paper is to contribute to our understanding of the chemical compositions of early Islamic glass vessels by comparing their archaeological date and typology. In the early Islamic period, glass objects were mainly produced from natron as the soda source. Among the natron glass analyzed in this study, glass vessels with low titanium and iron and high strontium contents, which were probably produced in the Syria–Palestine region, were excavated in the eighth century layer. From the ninth century layer, a large number of samples with high levels of calcium, titanium and iron, probably produced in Egypt, were found. It should be noted that a large number of glass vessels with this chemical composition were found at the Raya site, because this type of glass was rarely reported from other Islamic sites. We finally concluded that this type of glass seems to be produced under a fixed recipe, although some samples contain a colorant or decolorized materials.     

西周至南北自制玻璃概述

我国玻璃起步较晚,大体始于西周初或先周(殷末),主要是蓝色、浅蓝色或绿色玻璃珠管,与玉、玛瑙配合制成“杂佩”。其时玻璃的主要成分为二氧化硅,并含有少量铅、钡,故称为铅钡玻璃,与西方钠钙玻璃不同而独树一帜。春秋战国时期,西方蜻蜓眼玻璃珠输入我国,从此,以仿羊脂白玉美若明月的“隋侯珠”为代表的自制玻璃与外来玻璃并存。西方(大月氏)吹制玻璃术于汉魏传入我国之后,也出现了自制的空心玻璃器皿。     

Pliny the Elder and Sr–Nd isotopes: tracing the provenance of raw materials for Roman glass production

In Roman and Byzantine times, natron glass was traded throughout the known world in the form of chunks. Production centers of such raw glass, active from the 4th to 8th century AD, were identified in Egypt and Syro-Palestine. However, early Roman primary glass units remain unknown from excavation or scientific analysis. The ancient author Pliny described in 70 AD that besides Egyptian and Levantine resources, also raw materials from Italy and the Gallic and Spanish provinces were used in glass making. In this study, the primary provenance of 1st–3rd century AD natron vessel glass is investigated. The use of combined Sr and Nd isotopic analysis allows the distinguishing and characterizing of different sand raw materials used for primary glass production. The isotope data obtained from the glass samples are compared to the signatures of primary glass from known production centers in the eastern Mediterranean and a number of sand samples from the regions described by Pliny the Elder as possible sources of primary glass. Eastern Mediterranean primary glass has a Nile dominated Mediterranean Nd signature (higher than −6.0 ? Nd), while glass with a primary production location in the western Mediterranean or north-western Europe should have a different Nd signature (lower than −7.0 ? Nd). Most Roman glass has a homogeneous ⁸⁷Sr/⁸⁶Sr signature close to the modern sea water composition, likely caused by the (intentional) use of shell as glass raw material. In this way, strontium and neodymium isotopes now prove that Pliny's writings were correct: primary glass production was not exclusive to the Levant or Egypt in early Roman days, and factories of raw glass in the Western Roman Empire will have been at play.     

Glass on the Amber Road: the chemical composition of glass beads from the Bronze Age in Poland

The article discusses the chemical composition of 56 glass samples from 52 beads found in Poland at 13 archaeological sites (mainly cemeteries). The artefacts have been dated to the II–V period of the Bronze Age (=phases BzB–HaB; c. 1600–750/700 bc). The LA-ICP-MS method was applied. Two groups were distinguished in this assemblage based on a comparison of the MgO to K₂O ratio in glass: (i) high magnesium glass (HMG)—23; and (ii) low magnesium and high potassium glass (LMHK)—33 (29 matrix glass specimens and 4 decorative). In southern Poland, beads made of HMG and LMHK are often found in the same cemeteries. Analyses have shown that HMG was most probably made in Mesopotamia and that at least one cobalt glass is of Egyptian provenance. LMHK glass was made in Europe, most probably in Italy. Also, Italy was the most probable transit point for artefacts made of HMG en route to East-Central Europe.     

CHARACTERIZATION AND PROVENANCE OF LATE ANTIQUE WINDOW GLASS FROM THE PETRA CHURCH IN JORDAN*

Fifth‐ to seventh‐century window glass fragments from the Petra Church in Jordan were analysed by EPMA and spectrophotometry to characterize their optical properties and chemical composition. The objective of this study was to determine the provenance of the raw glass and the secondary production procedures of the window‐panes. Judging from the material evidence, both the crown window‐panes and possibly the rectangular samples were produced through glass‐blowing techniques. The chemical data show that the assemblage forms a homogeneous group of soda–lime–silica glass of the Levantine I type. The green glass, however, has higher silica and lower soda contents than the aqua‐blue fragments. The composition of one sample suggested the recycling of Roman glass. Our results confirm the trade of glass between the Levantine coast and Petra during Late Antiquity. No colouring agents other than iron were detected. Spectrophotometry confirmed the presence of iron and showed that the window fragments absorbed light relatively equally across the visible part of the spectrum. The windows thus seem to have provided an almost colourless illumination for the sacred interior.     

THE PROVENANCE AND TECHNOLOGY OF NEAR EASTERN GLASS: OXYGEN ISOTOPES BY LASER FLUORINATION AS A COMPLEMENT TO STRONTIUM*

The ability to make rapid measurements on small samples using laser fluorination enhances the potential of oxygen isotopes in the investigation of early inorganic materials and technologies. δ¹⁸O and ⁸⁷Sr/⁸⁶Sr values are presented for glass from two primary production sites, four secondary production sites and a consumer site in the Near East, dating from Late Antiquity to the medieval period. δ¹⁸O is in general slightly less effective than ⁸⁷Sr/⁸⁶Sr in discriminating between sources, as the spread of measured values from a single source is somewhat broader relative to the available range. However, while ⁸⁷Sr/⁸⁶Sr is derived predominantly from either the lime‐bearing fraction of the glass‐making sand or the plant ash used as a source of alkali, δ¹⁸O derives mainly from the silica. Thus the two measurements can provide complementary information. A comparison of δ¹⁸O for late Roman – Islamic glasses made on the coast of Syria–Palestine with those of previously analysed glasses from Roman Europe suggests that the European glasses are relatively enriched in ¹⁸O. This appears to contradict the view that most Roman glass was made using Levantine sand and possible interpretations are discussed.     

WASTE GLASS,VESSELS AND WINDOW‐PANES FROM THAMUSIDA (MOROCCO): GROUPING NATRON‐BASED BLUE–GREEN AND COLOURLESS ROMAN GLASSES

A collection of window‐panes, vessels and alleged waste from Thamusida has been investigated by OM, SEM–EDS, ICP–MS, ICP–OES and XAS at the Fe–K and Mn–K edges. Glass samples have been characterized as natron‐based soda–lime–silica glasses, with low magnesium and low potassium. The results have been compared with 43 reference groups available for ‘naturally coloured’ and colourless glasses of both Roman and later ages. Two main types were distinguished: RBGY 1 (R oman B lue–G reen and Y ellow 1) and RBGY 2 (R oman B lue–G reen and Y ellow 2). Given their compositional similarity to the Levantine I or, to a lesser extent, HIMT glasses, the Syrian–Palestinian coast for RBGY 2 and Egypt for the RBGY 1 have been suggested for their provenance. Most Thamusida samples have been assigned to the RBGY 2 type. A small group of Thamusida colourless vessels was included into the RC (R oman‐C olourless) compositional field; the latter still being defined. The alleged waste pieces may define a local production that should have been of secondary type. The investigations performed on local raw materials seem to discount the possibility of a primary glass‐making site. XAS measurements determined that Fe²⁺ contents ranging between 30 and 52% are able to assure an aqua blue colour; below 30%, the glasses turn light green or light yellow.     

The production technology of Egyptian blue and green frits from second millennium BC Egypt and Mesopotamia

The microstructures and chemical compositions of some 55 Egyptian blue and green frit samples from New Kingdom Egypt and 15th century BC Mesopotamia are determined using analytical scanning electron microscopy, the main focus being on frit cakes, powder residues, and frit vessel and bead fragments from one of the “factory areas” at Amarna in Middle Egypt. Replicate Egyptian blue frits produced in the laboratory are similarly investigated. Comparison of the microstructures of the ancient and replicate samples suggest that frit cakes are the primary product, and that these were ground to produce the powder, and then moulded to shape and refired to produce the vessels and beads. Egyptian blue and green frits are shown to be distinct pigments, the pigment produced depending on the relative proportions of copper oxide and lime in the mixtures. The bulk and glass phase compositions are used to try to infer the different sources of the quartz, lime, copper and alkali flux used in the production of frits from Egypt and Mesopotamia. An estimate is made of the scale of production of Egyptian blue frit in New Kingdom Egypt.     

ANALYSIS OF FIRST MILLENNIUM bc GLASS VESSELS AND BEADS FROM THE PICHVNARI NECROPOLIS,GEORGIA*

The Pichvnari necropolis on the Black Sea coast of Georgia lies in an area known in the late first millennium as ‘Colchis’, on part of the trade route leading to the Orient. The burials of the necropolis date to the late fifth century bc and frequently contain grave goods, including extremely well‐preserved polychrome glass beads and core‐formed vessels. This paper presents a study of these vessels both stylistically and archaeologically and using SEM–WDS and LA–ICPMS. It reveals that the vessels have compositional differences that may point to multiple manufacturing sites. One of the vessels appears stylistically unique and may exhibit one of the earliest uses of manganese as a decolorizer. Major and minor element data for the vessels suggest that they may belong to the same ‘Levantine’ group as many Roman glass objects, suggesting that a source of sand on the coast of the Levant could have been used in their production. The beads clearly show glass with both natron‐ and plant ash‐based flux with distinct rare earth compositions, showing multiple sites of production, some of which were probably either in the Middle East or the Indian subcontinent.     

Between east and west: Glass beads from the eighth to third centuries bce from Poland

The study analyses the chemical composition of 57 glass samples from 40 beads discovered at 20 archaeological sites in Poland. The beads are dated to Hallstatt C–Early La Tène periods (c.800/750–260/250 bce ). Analyses were carried out using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). Two groups were distinguished among the glasses based on the MgO/K₂O ratio: high-magnesium glass (HMG), five samples; and low-magnesium glass (LMG), 52 samples. The former were melted with halophyte plant ash, the second with mineral soda. These glasses were produced in the Eastern Mediterranean (more likely in Mesopotamia or Syro-Palestine than in Egypt) and transported in the form of semi-products to secondary glass workshops in Europe. Some of the white opaque glass was coloured and opacified in Europe.