Prior to the eighteenth century, cobalt was exclusively employed as a colouring agent for vitreous materials, and its use appears to be concurrent with the earliest large-scale production of glass ...during the Late Bronze Age (LBA). LBA cobalt deposits with a distinctive elemental signature have been identified in the oases of the western Egyptian desert, while cobalt mines in Kashan (Iran) and in the Erzgebirge (Germany) are known to have been exploited during the later Middle Ages. For most of the first millennium BCE and CE, however, the identity of cobalt sources and their supply patterns remain elusive. The aim of this study is to characterise the chemical composition of cobalt colorants used during the first millennium CE. Compositional variations indicate the use of different raw materials and/or production processes, which in turn has implications for the underlying exchange networks. Using mainly correlations between cobalt, nickel and zinc as discriminants, our results show that the compositional signature of cobalt underwent two major changes. An increase in the CoO/NiO ratios occurs between the late fourth and the beginning of the sixth century, while a new zinc-rich source of cobalt begins to be exploited during the second half of the eighth century in the Islamic world.
The archaeological excavation of the Villa dei Quintili in Rome (2nd century AD) brought to light one of the most impressive residential complexes of the Roman Empire. Among the astonishing number of ...findings, inside and outside the buildings, a large amount of glass mosaic tesserae were gathered from the thermal bath environments. This work reports the results of a microtextural and microchemical characterization of 29 colored opaque glass tesserae, by using an analytical approach that included the use of scanning electron microscopy with energy-dispersive X-ray spectroscopy, laser ablation-inductively coupled plasma-mass spectrometry. The glass is usually a soda-lime-silicate glass, with the exception of red and orange glass tesserae, which showed the typical composition of lead glasses mixed with plant ashes. Red tesserae were likely produced with a natron-based glass mixed with plant ashes, acting as flux and reducing agent. The opacifiers were all antimony-based with different natures according to the chemical composition: calcium antimonates (white in color) and lead antimonates (yellow in color).
In the 29 tesserae studied in this research, the colors of glass were strictly correlated to the concentrations of coloring agents, the two main coloring ions identified were copper, introduced in the majority of samples as bronze scrap, and cobalt. Finally, the levels of trace elements indicate the use of mature sand, rich in quartz and poor in heavy metals and clay minerals, for the production of all samples.
•Vitreous tesserae from Villa dei Quintili have been analyzed.•Chemical composition and production technology of vitreous tesserae have been determined.•SEM-EDS and LA-ICP-MS have been applied on vitreous tesserae analysis.
The results of a programme of compositional analysis on a series of emerald green glass vessels of known form and date suggest that emerald green vessels have distinct characteristics that set them ...apart from most contemporary glasses. These specific compositional peculiarities presented here will be evaluated in the context of the varieties of vessel forms produced in the colour. In the light of our findings we will suggest a number of ways forward in the understanding of the structure of the early Roman glass industry.
•1stC emerald green glass differs compositionally suggesting it was coloured at source.•It is not used for certain common forms raising questions of secondary supply systems.•Some forms have higher Pb, suggesting links to early Pb-Sb colourless glass production.•The alkali is ambiguous; low-K soda ash(es) or ash+natron (linked to colour formation).•The trace element fingerprint is complex, but an Egyptian provenance is proposed.
Aquileia (Italy) is one of the largest Roman cities so far excavated, and is on the UNESCO World Heritage List. The significant amounts of glass found in the site have suggested to many researchers ...that Aquileia played a central role in glass production and trade in ancient times, although only very few archaeometric data have been obtained so far. In this context, an archaeological and archaeometric study was conducted on 62 unintentionally coloured samples of Late Roman glass (late 3rd–6th centuries AD) from the excavation of the Casa delle Bestie Ferite (“House of the Wounded Animals”). Results indicate the importance of Aquileia in the glass trade. Bulk chemistry (EPMA and XRF data) evidences a compositional transition with respect to Early Roman glass (1st–3rd centuries AD), indicating changes in raw materials for glass-making. In particular, the chemical data show the close similarity between Aquileia glass and some of the main compositional groups widespread in the Mediterranean from the 4th century onwards (HIMT, Levantine I, Série 3.2), suggesting their probable common origin in the Eastern Mediterranean. This evidence suggests there was no primary glass production in Aquileia, as presumed in the past by some authors. No relationships between chemical composition, type, chronology or production technique have been observed, although the possible connection between HIMT-type glass and low-quality objects such as bottles cannot be completely excluded and must be better investigated in future research.
•The first systematic archaeometric study on Late Roman glass from Aquileia.•Both archaeological and chemical data are reported and discussed.•The identified compositional groups are similar to coeval ones from Mediterranean.•Low evidence of recycling, suggesting the use of “fresh” glass.•No relationships among composition, type, chronology and production technique.
A group of glass shards recovered from the fill of shaft tombs from the Third Intermediate Period on the Upper Terrace of the Temple of Hatshepsut in Deir el-Bahari consists for the most part of ...non-diagnostic body vessel fragments. At least 17 different vessels are attested in this assemblage, assigned to the 4th century AD, with only two pieces dated to the 1st–3rd centuriesAD. In addition to the vessels, a few windowpanes from the 6th–8th century AD were also found. This small group of glass finds is the first ever to be published from the Temple of Hatshepsut.
The process of degradation in artefacts subjected to centuries of burial can be of great relevance above all in archaeological glass. Infrared thermography is a non-destructive method allowing to map ...the defects of the glass substrate, both produced during its manufacturing (e.g., bubbles and inclusions) and due to ageing. This research is focused on the use of different flash thermography methods for the mapping of superficial flakes on Roman glasses dating back to the I and II century A.D. The effectiveness of active thermography methods is evaluated to map degraded portions of archaeological glass considering their semitransparency and specific optical absorption.
Laser ablation inductively coupled plasma mass spectrometry (LA‐ICP‐MS) analyses of loose glass tesserae from the Northwest Quarter of Gerasa/Jerash has enhanced our understanding of the dynamics ...regulating the production and circulation of glass tesserae in second‐ to eighth‐centuries ce Jordan and the diachronic development of mosaics at the site. The identification of Levantine and Egyptian compositions (Roman‐Mn, Levantine I, HIMT, Foy 2.1) proves the continuous production of mosaics from the second to the seventh centuries. The Levantine I tesserae were made by the recycling and colouring of glass cullet. The gilded tesserae, in contrast, were all of an Egyptian base glass, likely illustrating the import of finished tesserae.
In the past few years, deeply colored black-appearing glass has garnered a growing interest in the context of research on Iron Age glass technology and trade. The numerous ‘black’ glass beads found ...in Early Iron Age contexts of Southern Portugal have not however been considered in this discussion, and they remain largely unsystematized. In this contribution, a typological survey of these objects is presented which highlights their unusual concentration in a well-delimited area of Southern Portugal and their relatively circumscribed chronological setting. This is particularly striking when compared with other groups of beads, namely blue beads of various types, which are much more widespread and long-lasting. The global position of these beads is also considered, with typological comparisons and the few available compositional data suggesting that they may be the product of Punic, and perhaps specifically Carthaginian trade with the Western Iberian Peninsula. Finally, the possible specific historic context in which these beads arrived in Southern Portugal is considered.
The chemical composition of 48 glass finds from Histria and Tomis, Romania, chiefly dated to the 1st-4th c. AD, was determined using prompt gamma activation analysis (PGAA) at the Budapest Neutron ...Centre (BNC). Most fragments have composition typical for the Roman naturally colored blue-green-yellow (RNCBGY) glass; Mn-colorless, Sb-colorless, and Sb-Mn colorless glass finds were evidenced, too. Several Foy
and Foy
glass fragments, as well as an HIMT and a plant ash glass sample, were identified in the studied assemblage. The archaeological evidence, the glass working waste items, and the samples with compositional patterns suggestive of recycling are proofs of the secondary glass working activities at Tomis during the Early Roman Empire period.
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