Islamic Glass in the Making

The ancient glass industry changed dramatically towards the end of the first millennium. The Roman glassmaking tradition of mineral soda glass was increasingly supplanted by the use of plant ash as the main fluxing agent at the turn of the ninth century CE. Defining primary production groups of plant ash glass has been a challenge due to the high variability of raw materials and the smaller scale of production. Islamic Glass in the Making advocates a large-scale archaeometric approach to the history of Islamic glassmaking to trace the developments in the production, trade and consumption of vitreous materials between the eighth and twelfth centuries and to separate the norm from the exception. It proposes compositional discriminants to distinguish regional production groups, and provides insights into the organisation of the glass industry and commerce during the early Islamic period. The interdisciplinary approach leads to a holistic understanding of the development of Islamic glass; assemblages from the early Islamic period in Mesopotamia, Central Asia, Egypt, Greater Syria and Iberia are evaluated, and placed in the larger geopolitical context. In doing so, this book fills a gap in the present literature and advances a large-scale approach to the history of Islamic glass

Islamic Glass in the Making

The ancient glass industry changed dramatically towards the end of the first millennium. The Roman glassmaking tradition of mineral soda glass was increasingly supplanted by the use of plant ash as the main fluxing agent at the turn of the ninth century CE. Defining primary production groups of plant ash glass has been a challenge due to the high variability of raw materials and the smaller scale of production. Islamic Glass in the Making advocates a large-scale archaeometric approach to the history of Islamic glassmaking to trace the developments in the production, trade and consumption of vitreous materials between the eighth and twelfth centuries and to separate the norm from the exception. It proposes compositional discriminants to distinguish regional production groups, and provides insights into the organisation of the glass industry and commerce during the early Islamic period. The interdisciplinary approach leads to a holistic understanding of the development of Islamic glass; assemblages from the early Islamic period in Mesopotamia, Central Asia, Egypt, Greater Syria and Iberia are evaluated, and placed in the larger geopolitical context. In doing so, this book fills a gap in the present literature and advances a large-scale approach to the history of Islamic glass

Late Roman and early Islamic glass in Spain: production and consumption

info:eu-repo/semantics/publishedVersio

Streams across the Silk Roads? The case of Islamic glass from Ghazni

Abstract This paper presents data obtained by a combined chrono-typological and archaeometric study carried out on an assemblage of glassware and bracelets unearthed at the Ghaznavid Palace of Ghazni, Afghanistan. Pulsating trade and cultural centre located along the Silk Roads, the site of Ghazni has yielded evidence of an uninterrupted archaeological sequence, with settlement continuity spanning from pre-Islamic (2nd–9th/10th CE) to Islamic periods (end 10th–19th CE). Both glassware and bracelets were manufactured by using a plant ash-based glass, in line with Central Asian glassmaking technology. Furthermore, several compositional groups were identified, showing close affinities with other assemblages from Central Asia, Uzbekistan and Jordan

The role of sulphur in the early production of copper red stained glass

Little is known about the production of ruby red copper stained glasses from the Medieval and Renaissance periods apart from the fact that the colour is due to the presence of small metallic copper nanoparticles and that tin, the most common reducing agent used in copper red glass production since the 19th century, is not present. In fact, very few workshops in Europe were able to make red glass in historical times, and they kept it secret, so very little is known about how it was obtained. These workshops exported the red glass throughout Europe. Recently, the presence of copper sulphide particles and the data obtained in the replication red glass following historical recipes suggested that sulphur might be the key ingredient in this process. Here, a collection of historical red glasses from these periods has been analysed using a combination of microanalytical techniques; Electron Microprobe (EM) and Field Emission and Scanning Electron Microscopy (FESEM) to verify the chemical composition and nanostructure of the glasses, Synchrotron radiation micro-X-Ray Diffraction (micro-XRD) to establish the nature of the nanocrystalline precipitates, and S, Cu and Fe K-edge micro-X-Ray Absorption Spectroscopy (micro-XAS) to determine the speciation. The data obtained show that the oxidation of S2- into S6+ in the glass is responsible for the precipitation of copper nanoparticles. The development of a sulphide-silicate partition and the presence of Fe3+ in the melt give rise to the precipitation of the high-pressure tetragonal polymorph of chalcocite (Cu2S). Differences between the Medieval and Renaissance red glass are determined.Peer ReviewedPostprint (published version

Composition and origins of decorated glass from Umayyad Cordoba (Spain)

Recent archaeological excavations carried out in the western suburbs of Cordoba (Spain) brought to light numerous fragments of archaeological glass from the caliphal period (929–1031 CE). The typological and compositional analysis by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) of 66 fragments enabled the identification of different types of base glass and glass working techniques, identifying local productions, imports and decorative imitations of eastern models. The studied fragments include Mesopotamian, Levantine, Egyptian and possibly Sicilian soda-rich plant ash glass categories, and various glass-decorating techniques such as mould-blowing, pressing, cutting, staining or gilding. The systematic comparison of the trace element patterns of several relief-cut objects identified both imported ware and a locally manufactured sample, whereas all mould-blown pieces were made from locally sourced raw materials. Iberian glassworkers seem to have preferred mould-blowing, probably because of the distinct working properties of locally available high lead glass. The results thus confirm the continuous long-distance exchange of vitreous material, as well as the existence of multiple glassmaking centres in the Iberian Peninsula, illustrating a link between secondary glass working techniques and chemical composition. Furthermore, the identification of several fragments belonging to the same object based on chemical composition allowed us to reconstruct entire vessels and thereby expand the repertoire of known typologies circulating in Umayyad Spain.info:eu-repo/semantics/publishedVersio

Glass import and production in Hispania during the early medieval period: The glass from Ciudad de Vascos (Toledo)

One hundred and forty-one glass fragments from medieval Ciudad de Vascos (Toledo, Spain) were analysed by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The glasses fall into three types according to the fluxing agents used: mineral natron, soda-rich plant ash, and a combination of soda ash and lead. The natron glasses can be assigned to various established primary production groups of eastern Mediterranean provenance. Different types of plant ash glasses indicate differences in the silica source as well as the plant ash component, reflecting changing supply mechanisms. While the earlier plant ash groups can be related to Islamic glasses from the Near East, both in terms of typology and composition, the chemical signature of the later samples appear to be specific to glass from the Iberian Peninsula. This has important implications for our understanding of the emerging glass industry in Spain and the distribution patterns of glass groups and raw materials. The plant ash that was used for the Vascos glasses is rich in soda with low levels of potash, similar to ash produced in the eastern Mediterranean. It could therefore be possible that Levantine plant ash was imported and used in Islamic period glass workshops in Spain. Unlike central and northern Europe where an independent glass industry based on potassium-rich wood ash developed during the Carolingian period, the prevalence of soda ash and soda ash lead glass on the Iberian Peninsula indicates its commercial and technological interconnection with the Islamic east. Our study thus traces several stages leading to the development of a specifically Spanish primary glassmaking industry

The first glass of al-Andalus: analytical evidence from the early Islamic site of Cabezo Pardo (Alicante)

Se presentan por primera vez para la Península Ibérica los resultados del análisis químico de dos objetos de vidrio de cronología emiral temprana procedentes del yacimiento de Cabezo Pardo (San Isidro, Alicante). El examen por LA-ICP-MS de su composición indica que se trata de vidrios sódico-cálcicos fabricados con natrón como fundente. Sus características permiten encuadrarlos en dos de los grupos más difundidos en la antigüedad tardía: HIMT y Foy 2. El primer caso, una lámpara, podría ser resultado de una perduración del uso de un objeto antiguo a lo largo del tiempo tal vez relacionado con las poblaciones mozárabes y/o muladíes que habitaron el yacimiento. El segundo objeto, posiblemente una botella, fue elaborado a partir de vidrio reciclado. Sus características permiten encuadrarlo dentro del subgrupo Foy 2.2. Una composición poco frecuente también documentada en Francia e Italia cuya cronología suele situarse entre la segunda mitad del siglo VII y finales del siglo VIII d.C.This paper discusses the LA-ICP-MS analysis of two well dated glass objects from Cabezo Pardo (Alicante), the first ones to be published in the Iberian Peninsula that date to the early Emiral period. The data characterise the fragments as soda lime silica glasses made using natron as flux. Compositionally, they correspond to two of the most widespread late antique primary glass production groups: HIMT and Foy 2. The first sample, a glass lamp, may be the result of the continuous use of an ancient artefact, perhaps related to the Mozarabic and/or Muladí population that inhabited the site. The second object, possibly a bottle, was made from recycled glass. Its chemical signature is consistent with the so-called Foy-2.2 group, a scarce composition that has previously been documented in France and Italy. It can date between the second half of the 7th century and the end of the 8th century CE.Las excavaciones arqueológicas de Cabezo Pardo han sido realizadas bajo la dirección del Museo Arqueológico de Alicante formando parte del Plan de Excavaciones de la Diputación Provincial de Alicante e integradas en el proyecto HAR2015-67111-P: El sitio de las cosas: relación entre la cultura material y los espacios construidos a la luz de la arqueología (ss. VI-XIV) de la Universidad de Alicante y financiado por el Ministerio de Economía y Competitividad dentro del Programa Estatal de Fomento de la Investigación Científica y Técnica de Excelencia. Este proyecto ha recibido financiación del European Research Council (ERC) bajo el Programa de investigación e innovación Horizonte 2020 de la Unión Europea (Grant Agreement No. 647315 to NS)

Modernist enamels: composition, microstructure and stability

Coloured enamels from the materials used in Modernist workshops from Barcelona were produced and compared to those found in the buildings to explore the reason for the reduced stability of the blue and green enamels. They were made of a lead-zinc borosilicate glass with a low softening point, reasonable stability to corrosion and matching thermal expansion coefficient with the blown base glass, mixed with colourants and pigment particles. The historical enamels show a lead, boron and zinc depleted silica rich amorphous glass, with precipitated lead and calcium sulphates or carbonates, characteristic of extensive atmospheric corrosion. The blue and green enamels show a heterogeneous layered microstructure more prone to degradation which is augmented by a greater heating and thermal stress affectation produced by the enhanced Infrared absorbance of blue tetrahedral cobalt colour centres and copper ions dissolved in the glass and, in particular, of the cobalt spinel particles