Tracing the origins of Eastern European enamelling: Chemical composition of glass and enamels from the Bryansk hoard (south‐western Russia)

The chemical composition of a series of Eastern European enamels from the Bryansk hoard from the third century ad and other sites was studied using scanning electron microscopy with energy‐dispersive spectroscopy (SEM‐EDS) and electron microprobe analysis (EPMA) techniques. Red opaque glass is homogeneous compositionally, suggesting not only common manufacturing traditions but also identical types and sources of raw materials and, consequently, a single origin. The glass is made in the Roman tradition of enamelling, which appeared in the mid‐first century ad , as was the case with orange glass. The difference in the lead content in glass of different colours, which determines the melting temperature, allows the reconstruction of polychrome enamelling techniques.     

The Chronology of Insiza Cluster Khami‐Phase Sites in South‐Western Zimbabwe: Compositional Insights from pXRF and Raman Analysis of Excavated Exotic Glass Finds

Fourteen glass beads and one glass fragment from Khami‐period (ad 1400–1830) sites of Danamombe, Naletale, Gomoremhiko, Nharire and Zinjanja, in Zimbabwe, were analysed by pXRF and Raman spectroscopy with the intention of correlating the results with associated radiocarbon dates. The results show that Zinjanja and an earlier part of the Danamombe stratigraphic context had Khami Indo‐Pacific beads (15th–17th centuries) corresponding with Torwa occupational layers. Other European beads and one bottle fragment [high‐lime, low‐alkali (HLLA) glass] dating from the 16th to the 19th centuries were confined to the top stratigraphic layers of Danamombe and Naletale, which coincide with the later Rozvi occupational layers. Gomoremhiko had one Mapungubwe–Zimbabwe bead series (13th–15th centuries), which suggests that it was probably earlier than the other sites. All European beads are made of soda–lime plant‐ash glass with high alumina, which makes them comparable with glass produced through the Mediterranean traditions in Southern Europe.     

Characterization of some ancient glass beads unearthed from the Kizil reservoir and Wanquan cemeteries in Xinjiang,China

A total of 33 ancient glass beads unearthed from the Kizil reservoir cemetery and Wanquan cemetery in Xinjiang are studied using Raman spectroscopy, scanning electron microscopy with energy‐dispersive spectrometry (SEM–EDS) and other methods. The detailed study of the glassy matrices, the crystalline inclusions and the microstructural heterogeneities for these glass beads has revealed some valuable information to help in the understanding of their possible manufacturing technology and provenance. At least two different types of glass were present in the two cemeteries. For the first time, antimony‐based colourant/opacifier—for example, Pb₂Sb₂O₇ or CaSb₂O₆—was systematically identified in some beads of plant‐ash type soda–lime glass dated to about 1000–500 bc . The limited number of potash glass beads from the Kizil reservoir cemetery, which were dated to about 500–300 bc , used tin oxide as an opacifier. The diverse resources of the soda–lime and potash glasses indicate the existence of a complex trade network between China and the West much earlier than the Western Han Dynasty.     

An archaeometric contribution to the characterization of Renaissance maiolica from Urbino and a comparison with coeval maiolica from Pesaro (the Marches,central Italy)

The results of an archaeometric trial study performed on an important finding of Renaissance maiolica (mid‐15th to early 16th century) from the Ducal Palace of Urbino are presented. Mineralogical–petrographic data (XRD, OP, SEM–EDS) and chemical characterization (ICP/AES–MS: major and trace elements) of both ceramic bodies and glazes were compared with similar data provided on coeval maiolica found in archaeological excavations in Pesaro, now stored in the city's Municipal Museum, in order to verify an origin of the potteries from common (Pesaro) or different (Pesaro and Urbino) production centres. The results indicate that ceramic bodies were produced with quite similar illitic–calcareous clays, most probably taken from the same local Pliocene Formation. Similarities were also found concerning the glaze's glass (silica–lead), colourants (cobalt, copper and manganese) and pigments (lead antimonate and cassiterite).     

Silk Road glass in Xinjiang,China: chemical compositional analysis and interpretation using a high-resolution portable XRF spectrometer

In this paper we explore the major, minor and some trace elements of sixty-five glass beads from eighteen oasis sites both north and south of the Taklamakan Desert, the ancient centre of the Silk Routes linking East and West; the samples date from the Warring States period (475–2211 BCE) to the Tang Dynasty (618–907 CE). Using a high-resolution portable XRF spectrometer, with special attention to issues of surface weathering and sample preparation, we obtained quantitative chemical compositional data that, when combined with archaeological context and the technology of bead manufacture, provide the basis for an understanding of both changes in glass type over time, and possible source areas for the Xinjiang glasses. While glass beads at the early sites (1st c. BCE to 4th c. CE) were coming primarily from Kushan-controlled territories in northern India, Pakistan and Afghanistan, with a small contribution from central China, most of the later glass (4th–10th c. CE) is similar to that produced in the Sasanian Empire at such sites as Veh Ardashir in central Iraq. These changes most likely reflect changing cultural and economic conditions in the Silk Road towns.     

Western Mediterranean sand deposits as a raw material for Roman glass production

During the Late Roman and Byzantine period, natron glass was made from its raw materials in a limited number of primary production centres in Egypt and Syro-Palestine. For the earlier Hellenistic and Roman period, no primary furnaces have been found and the location of primary production during this era remains unclear. Ancient authors such as Strabo and Pliny the Elder suggest that glassmaking sands were found near the River Belus (Israel), in Egypt, near the mouth of the Volturno River (Italy) and also in Spain and France. However, primary production in the western part of the Mediterranean is not supported by any direct archaeological evidence and possible sand raw materials from these regions have never been evaluated for their suitability to produce glass.     

Chemical analysis of 17th century Millefiori glasses excavated in the Monastery of Sta. Clara-a-Velha,Portugal: comparison with Venetian and façon-de-Venise production

A set of ten Millefiori glass fragments dating from the 17th century, originated from archaeological excavations carried out at the Monastery of Sta. Clara-a-Velha (Coimbra, Portugal), were characterized by X-ray electron probe microanalysis (EPMA), Raman microscopy and UV–Visible absorption spectroscopy. All glasses are of soda-lime-silica type. The use of coastal plant ash is suggested by the relatively high content of MgO, K₂O and P₂O₅, as well as by the presence of chlorine. Tin oxide or calcium antimonate were the opacifiers used in the opaque glasses, cobalt in the blue glasses, copper in the turquoise glasses, iron in the yellow and greenish glasses, and iron and copper were found in the opaque red and aventurine glasses. Based on the concentrations of alumina and silica four different sources of silica were identified, allowing the classification of the glasses into the following compositional groups: low alumina (<2 wt%), which includes a sub-group of cristallo samples with SiO₂ > 70 wt%, medium alumina (2–3 wt%), high alumina (3–6 wt%) and very high alumina (>6 wt%). Comparison with genuine Venetian and façon-de-Venise compositions showed that two fragments are of Venetian production, one of Venetian or Spanish production and the remaining are of unknown provenance. In two fragments the glass of the decoration is probably Venetian or Spanish but the glass used in the body is also of unknown provenance.     

Energy dispersive X-ray fluorescence analysis of 1st millennium ad glass from Britain

A series of energy dispersive X-ray fluorescence analyses has been undertaken in response to archaeological problems relating to 1st millennium AD glass excavated in Britain. The aim of the work was to furnish a set of comparable analytical results to be used in assessing hypotheses concerning the general state and development of glass technology through this period. Within this framework, however, it has also been possible to attempt answers to specific archaeological questions relating to material from particular sites. The paper discusses the background to, and the interpretation of such results, particulars of the analytical technique used, a general overview of approximately 200 analyses and three examples of the use of this data in relation to specific archaeological problems.     

两件秦代铅钡玻璃腐蚀特征研究

铅钡玻璃是我国特有的玻璃体系，主要集中在战国至两汉时期。随着越来越多的铅钡玻璃完整器被发现，相关的风化腐蚀研究和保护工作逐渐展开。本研究以陕西临潼新丰秦墓和河南三门峡秦墓出土的两件秦代(公元前221—公元前207)铅钡玻璃为样本，采用光学显微镜、扫描电子显微镜、激光拉曼光谱仪对铅钡玻璃的腐蚀层进行成分与结构分析，结果表明铅钡玻璃腐蚀层的钡大部分流失至环境或腐蚀层外侧，腐蚀层的主要物相为碳酸铅。腐蚀层的形成与铅钡玻璃埋藏环境中水位和酸碱度的周期性变化有关。本研究对铅钡玻璃保护工作具有参考价值，也为古代玻璃文物的预防性保护提供了有益的信息。     

‘Water mixed with the blood of Thomas’: contact relic manufacture pictured in Canterbury Cathedral’s stained glass

Four remarkable stained glass panels in the Trinity Chapel of Canterbury Cathedral (executed c.1185–1220) picture the mixing of Thomas Becket’s blood with water at Becket’s tomb. The ‘water of St Thomas’ was among the most widely renowned medieval water relics, reputed to have healed the sick throughout Latin Christendom. This article examines the glass images, comparing them with narratives in the glaziers’ source text, Benedict of Peterborough’s collection of Becket’s miracles. The glaziers presented an enhanced and carefully designed version of the early history of the water relic: the visual images draw strong parallels between the water of St Thomas and the Eucharist, and trumpet the role of the monks of Christ Church Cathedral Priory, Canterbury, the patrons of the glass, in the mixing process. The glass panels also provide suggestive evidence regarding the personnel, vessels and ceremonial involved in the actual mixing of the relic at Canterbury, including the likely participation of a lay sacrist and the possible use of mazers.