Visigothic Jewellery: A Technical Study of Glass Used as Gems in Belt Buckles from a Spanish Necropolis

In this work, we studied coloured and colourless glass used as gems in Visigothic buckles possibly originating from the necropolises of Torredonjimeno, Duraton or Castilltierra in Spain. Scanning electron microscopy (SEM) with energy‐dispersive analysis (EDS) and observations made with an optical microscope in reflected and transmission mode were performed in order to establish the composition, origin of the colour and decay process of these glass pieces. The chemical analysis of ancient glass can provide relevant information regarding the manufacturing approach used during a specific period. The results revealed the presence of various transition metal elements used as chromophore elements, as well as some metallic backing foils used to improve the colour of pieces of almost colourless glass.     

Natron as a flux in the early vitreous materials industry: sources,beginnings and reasons for decline

Natron deposits, the best known of which being those at Wadi Natrun in Egypt, have been used as the flux in the production of vitreous materials from the early 4th millennium BC onwards. In the present paper, the history of the use of natron as a flux is traced from its beginnings in the glaze of Badarian steatite beads, through its use in glass production starting in the 1st millennium BC, until its apparent shortage during the 7th to 9th centuries AD, and its subsequent replacement by plant ash during the 9th century AD. Documentary evidence for possible natron sources in Egypt, including the Wadi Natrun, and around the eastern Mediterranean is summarised, and the results of recent fieldwork at the Wadi Natrun and at al-Barnuj in the Western Nile Delta are presented. The possible reasons for the apparent shortage of natron from 7th to 9th centuries AD and its subsequent replacement by plant ash as the flux used in glass production during the 9th century AD are then considered. These include the possibility that, because of the massive scale of glass production, the demand for natron exceeded its supply; the possible effect of climatic changes; and the potentially disruptive role of political events in the Wadi Natrun–Delta region.     

Analyses of colourless Roman glass from Binchester,County Durham

Forty samples of Roman colourless glass tableware from Binchester, dating from the 1st to mid-3rd centuries AD, were analysed using ICP spectrometry and parallels were sought with similar studies of Roman glass from Colchester and Lincoln [C. Mortimer, M.J. Baxter, Analysis of Samples of Colourless Roman Vessel Glass from Lincoln, Ancient Monuments Laboratory Report 44/1996, 1996; H.E.M. Cool, J. Price, Roman vessel glass from excavations in Colchester, 1971–1985, Colchester Archaeological Report 8, Colchester Archaeological Trust Ltd. and English Heritage, Colchester, 1995; M.P. Heyworth, M.J. Baxter, H. Cool, Compositional Analysis of Roman Glass from Colchester Essex, Ancient Monuments Laboratory Report 53/1990, 1990]. Some samples from the Binchester, Colchester and Lincoln (BCL) groups were re-analysed using energy dispersive spectrometry (SEM–EDS) and the results were used to compensate for the differences in reproducibility between the ICP data sets, so that these could be directly compared. The majority of the glass from all three sites was similar but some distinct compositional characteristics were identified that were specific to certain types of ware. There were differences in the concentration of lead in the samples, which appear to be to some extent chronological. The compositional data for the glass from Binchester, Colchester and Lincoln were also compared to literature data for various types of natron glass produced in the 1st millennium AD.     

Southern African glass beads: chemistry,glass sources and patterns of trade

Three-hundred-and-sixty glass beads from 19 archaeological sites in southern Africa dating between about the 8th and 16th centuries AD were analyzed using LA-ICP-MS, determining 47 chemical elements. The eight different bead series, previously defined on morphological characteristics, possess different glass chemistries. Some bead series were made from plant-ash glasses, others from soda-alumina glasses. Zhizo series beads of the late 1st millennium AD were probably made from Iranian glass. Later bead series were made of glass probably manufactured in South Asia, though there are changes through time in both South Asian glass recipes and bead morphologies.     

Glass gilding process in medieval Syria and Egypt (13th–14th century)

Twelve gilded and enamelled Islamic glass fragments, produced in Syria or Egypt during the Ayyubid or Mamluk period, were provided by the Louvre museum for complete non-destructive analysis. The enamelling process of similar objects has been extensively studied in the last decades, but the gilding process has never been investigated in details. This paper focuses on the understanding of both the gilding process and the gold/glass adhesion mechanism. The structure, composition and thickness of the gold flakes forming the gilding decoration are measured. The complete process combining gilding and enamelling is described and the local mechanism of adhesion of gold flakes on the glass body is discussed.     

Mineral soda alumina glass: occurence and meaning

Mineral soda–alumina (m-Na–Al) glass has been found across a vast area stretching from Africa to East Asia. m-Na–Al glass appears around the 5th c. B.C. and is relatively common for periods as late as the 19th c. A.D. It is particularly abundant in South Asia, where raw materials to produce m-Na–Al glass are readily available, and was likely manufactured there; however, the number and the importance of the manufacturing centers is unknown as archaeological information are extremely scarce. The interpretation of data obtained using compositional analysis on a large corpus of artifacts (486) shows that at least five sub-groups of m-Na–Al glass can be identified using the concentrations of calcium, magnesium, uranium, barium, strontium, zirconium and cesium measured with laser ablation – inductively coupled plasma – mass spectrometry (LA-ICP-MS). From this data, it is possible to infer the existence of several m-Na-Al glass making centers, not all of them located in South Asia as previously assumed. They were operating over different time periods and were connected to different exchange networks.     

Glass Trade Beads from the Goose Lake Outlet #3 Site (20MQ140), Marquette County,Michigan

This article describes analyses of the glass trade-bead assemblage of the Goose Lake Outlet #3 (GLO#3) site (20MQ140), a probable short-term winter campsite located in the Upper Peninsula of Michigan. Based on typological and attribute analysis of the beads, which employed the Kidd and Kidd classification system and comparison with published “glass bead periods” or GBPs developed for assemblages in Ontario, the GLO#3 bead assemblage is assigned a date within the 1630s. Comparison with other midwestern protohistoric assemblages further supports this interpretation. Situated within a protohistoric period of intercultural interaction and exchange, the material culture from the site provides archaeological evidence for some of the earliest arrivals of European-made trade items in the Midwest.     

安徽当涂东晋墓发掘简报--兼论出土的玻璃碗残片类别和来源

当涂东晋墓的发掘,除出土了东晋墓中常见的青瓷器外,最大收获是发现了4片玻璃碗残片,经检测定性分析,它与当时国产玻璃成分不同,与湖北鄂城西晋墓出土的玻璃碗成分相似,同为舶来品萨珊玻璃器。它的发现为六朝时期中国南方与西方国家进行商品贸易方面的研究提供了实物资料。     

鲁国故城遗址出土蜻蜓眼玻璃珠的科学研究

本研究利用能量色散型XRF、共聚焦激光拉曼光谱分析技术、光学相干层析成像技术、超景深光学显微系统等多种无损分析技术对山东曲阜鲁国故城遗址出土的7颗蜻蜓眼玻璃珠进行了科学研究。基于获取的蜻蜓眼珠化学成分、物相结构、内部物理结构、表面显微形貌等相关信息,确定了这批蜻蜓眼玻璃珠的成分体系、制作工艺、产地来源和器物功能。研究结果表明,蜻蜓眼玻璃珠来自于楚地,是当时社会稀有而珍贵的奢侈品,是鲁国与楚地相互交流与联系的实物证据。     

Florence baptistery: chemical and mineralogical investigation of glass mosaic tesserae

A recent restoration of the mosaics of the Baptistery in Florence enabled the collection and analysis of a group of glass tesserae. Twenty-three tesserae, dated between the end of the 13th century and the first half of the 14th century, showing different colors were sampled and analyzed to identify the raw materials, colorants and opacifiers employed in their production.