- London, London, City of, United Kingdom
Ian Freestone
University College London, Institute of Archaeology, Faculty Member
- Archaeometry, Archaeological Science, Ancient Technology (Archaeology), Ancient Glass Analysis, Ceramic Petrography, Archaeometallurgy, and 18 moreAncient Glass, Science for Conservation and Restoration of Cultural Heritage, Chaîne Opératoire, Byzantine glass, Islamic Glass, Roman Glass, Glass Beads, Stained Glass, Ceramics (Archaeology), Glass (Archaeology), Medieval Glasses (Archaeology), portable XRF (PXRF) in Archaeology and Museum Science, Islamic Archaeology, Ancient Metallurgy, Byzantine Archaeology, Ceramic Glaze Technology, Glass, and Archaeological Chemistryedit
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Twenty-six glass bracelets and three finger rings from an Ayyubid-Mamluk (1179–1517 CE) cemetery at Dohaleh, North Jordan, have been analysed by electron microprobe. They fall into six compositional groups, based upon their alkali- and... more
Twenty-six glass bracelets and three finger rings from an Ayyubid-Mamluk (1179–1517 CE) cemetery at Dohaleh, North Jordan, have been analysed by electron microprobe. They fall into six compositional groups, based upon their alkali- and silica-related components. Groups A and F were made using Levantine plant ash but differ in their silica sources, they are typically decolorized using manganese. Groups B, C and E overlap in terms of silicarelated components but may be sub-divided on the basis of alkali source; this appears to have been a mineral alkali, possibly from Anatolia. A single bracelet (Group D) shows characteristics of Mesopotamian glass. All groups show evidence of tin-opacification, but the color palette of the mineral soda glasses is more restricted; furthermore, they were not decolorized using manganese. The results suggest that glass bracelets were being obtained from a wide range of sources.
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Our understanding of early copper metallurgy in the Iberian Peninsula is mostly based on analysis from wellstudied regions in the Southeast and Southwest. This paper focuses on two recently recovered Chalcolithic metallurgical assemblages... more
Our understanding of early copper metallurgy in the Iberian Peninsula is mostly based on analysis from wellstudied regions in the Southeast and Southwest. This paper focuses on two recently recovered Chalcolithic metallurgical assemblages outside these traditional research foci: two slagged crucibles from Lugar Viejo III (Zaragoza) and two large slag cakes from Cueva del Cañaveralejo (Córdoba). Analysis of the compositions and microstructures of the artifacts using optical microscopy and scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) suggests they are related to primary copper production, namely smelting in cruciblefurnaces under relatively oxidizing conditions, as is standard for this period. The slag layers on crucibles from Lugar Viejo indicate the production of copper with minor amounts of arsenic, also typical for this period. Of special note is the use of organic temper in the crucibles from Lugar Viejo, a practice found at the nearby site of Moncín but rare at other sites in Iberia. However, the slags from Cueva del Cañaveralejo are atypical in their large size (approx. 125 g each), fayalitic composition, unusual efficiency as demonstrated by a low copper content, and lack of arsenic; furthermore, the high sulfur content raises the possibility of the use of sulfidic ores. Results from both sites are compared against published data from well-known sites such as Los Millares, Las Pilas, Almizaraque, and Bauma del Serrat del Pont. The new data from Lugar Viejo and Cueva del Cañaveralejo reinforce the interpretation of metallurgy in the Iberian Peninsula as a low-skilled, conservative technology but also indicate the need for more research into regional variations. (See Supplementary Data 1 for a summary in Spanish).
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Major and trace elements are presented for 149 glass fragments ranging in date from the Roman to Early Islamic periods (1st – mid-8th centuries CE), excavated during the Danish-German Jerash Northwest Quarter Project's fieldwork between... more
Major and trace elements are presented for 149 glass fragments ranging in date from the Roman to Early Islamic periods (1st – mid-8th centuries CE), excavated during the Danish-German Jerash Northwest Quarter Project's fieldwork between 2011 and 2016. The results confirm a clear dominance of Levantine glass types, but also reveal 12 glasses of Egyptian and Mesopotamian compositions recovered from two houses destroyed by the major earthquake which hit parts of the Levant in January 749 CE. These closed and undisturbed contexts from the final phase of occupation reveal the presence of relatively more pristine Levantine as well as imported material that is less visible in earlier contexts in the Gerasa assemblage, where the recycling indexes are high and chemical signatures of any exotic glass were largely lost due to remelting and their dilution by the overwhelming quantities of glass produced in the Levantine region. This emphasizes that imported glass may frequently be underestimated or even invisible in glass compositional studies, depending on the archaeological context sampled and the approach taken to artifact quantification.
Levantine glass was attributed to Roman, Late Roman (Jalame) and Byzantine/Early Islamic (Apollonia) productions based primarily on MnO, Al2O3 and Na2O concentrations, which offered an advantage over previous approaches. While colorants in weakly colored glass indicate recycled material, their concentrations are sensitive to context, with higher concentrations in the early periods when the use of intentionally colored glass was more frequent. We have therefore developed the concept of the intensity of recycling, which was estimated using components modified during prolonged melting, such as K2O, P2O5 and Cl. A pronounced enrichment in CaO, also dependent upon the intensity of recycling, may affect the assignment to compositional groups and should be taken into consideration in future. Recycling in Gerasa appears to have been more intensive than was the case for cities closer to the primary production centers on the Mediterranean coast, consistent with the view that the dependency on recycling increases further away from the source of the primary material. In contrast, the cities in the coastal plain could readily exploit the marine transportation network, which appears to have played a major role in the distribution of raw glass.
Levantine glass was attributed to Roman, Late Roman (Jalame) and Byzantine/Early Islamic (Apollonia) productions based primarily on MnO, Al2O3 and Na2O concentrations, which offered an advantage over previous approaches. While colorants in weakly colored glass indicate recycled material, their concentrations are sensitive to context, with higher concentrations in the early periods when the use of intentionally colored glass was more frequent. We have therefore developed the concept of the intensity of recycling, which was estimated using components modified during prolonged melting, such as K2O, P2O5 and Cl. A pronounced enrichment in CaO, also dependent upon the intensity of recycling, may affect the assignment to compositional groups and should be taken into consideration in future. Recycling in Gerasa appears to have been more intensive than was the case for cities closer to the primary production centers on the Mediterranean coast, consistent with the view that the dependency on recycling increases further away from the source of the primary material. In contrast, the cities in the coastal plain could readily exploit the marine transportation network, which appears to have played a major role in the distribution of raw glass.
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The paper presents a set of glass fragments excavated at several different locations within and outside the late Roman fortified imperial residence Felix Romuliana (Gamzigrad, Serbia). This small group of eighteen fragments and mosaic... more
The paper presents a set of glass fragments excavated at several different locations within and outside the late Roman
fortified imperial residence Felix Romuliana (Gamzigrad, Serbia). This small group of eighteen fragments and mosaic glass
tesserae are distinguished by their cobalt blue colour. The majority of the finds are mosaic tesserae (six pcs) and sheets of glass
(five pcs), which could be related to architectural decoration (sectilia panels). Others are pieces left behind from secondary glass
working (four pcs). There are also two fragments tentatively identified as window pane pieces, and only one find is a vessel sherd.
The materials are dated to the 4th century. Significantly, some of the production debris and the two “window pane” fragments
were found inside the destruction of a glass furnace. The analyses of the chemical glass composition of the finds confirmed that
the blue colourant in all samples is cobalt, and antimony is also present at notable levels (except for one sample), likely to produce
opacification of the glass. Regarding the origin of the raw glass, the data on almost all pieces suggests a Syro-Palestinian
provenance, and a single sample could be related to Egyptian primary glass production. Importantly, the concentrations of the
oxides added to the base glasses in order to modify the colour are positively correlated in certain samples, hinting at the makeup
of the cobalt bearing ingredient and at a likely existence of particular production practices of the late Roman period.
fortified imperial residence Felix Romuliana (Gamzigrad, Serbia). This small group of eighteen fragments and mosaic glass
tesserae are distinguished by their cobalt blue colour. The majority of the finds are mosaic tesserae (six pcs) and sheets of glass
(five pcs), which could be related to architectural decoration (sectilia panels). Others are pieces left behind from secondary glass
working (four pcs). There are also two fragments tentatively identified as window pane pieces, and only one find is a vessel sherd.
The materials are dated to the 4th century. Significantly, some of the production debris and the two “window pane” fragments
were found inside the destruction of a glass furnace. The analyses of the chemical glass composition of the finds confirmed that
the blue colourant in all samples is cobalt, and antimony is also present at notable levels (except for one sample), likely to produce
opacification of the glass. Regarding the origin of the raw glass, the data on almost all pieces suggests a Syro-Palestinian
provenance, and a single sample could be related to Egyptian primary glass production. Importantly, the concentrations of the
oxides added to the base glasses in order to modify the colour are positively correlated in certain samples, hinting at the makeup
of the cobalt bearing ingredient and at a likely existence of particular production practices of the late Roman period.
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Relatively little is known about stained glass windows in England predating c. 1170; however, art-historical evaluation by Caviness (1987) argued that four figures from the “Ancestors series” of Canterbury Cathedral, usually dated to the... more
Relatively little is known about stained glass windows in England predating c. 1170; however, art-historical evaluation by Caviness (1987) argued that four figures from the “Ancestors series” of Canterbury Cathedral, usually dated to the late 12th and early 13th century, in fact date earlier (c. 1130-1160). This would place them amongst the earliest stained glass in England, and the world. Building on our previous work, we address Caviness’s hypothesis using a methodology based upon analysis of a few, well-measured heavy trace elements and a 3D-printed attachment for a pXRF spectrometer that facilitates in situ analysis. The results confirm two major periods of “recycling” or re-using medieval glass. The first is consistent with Caviness’s argument that figures predating the 1174 fire were reused in the early 13th century. The results suggest that in addition to figures, ornamental borders were reused, indicating the presence of more early glass than previously thought. In the second period of recycling (1790s), surviving figures from the Ancestors series were removed and adapted into rectangular panels for insertion into large Perpendicular-style windows elsewhere in the cathedral. The results show that the glasses used to adapt the panels to a rectangular shape were broadly contemporary with the glasses used to glaze the original Ancestors windows, again representing a more extensive presence of medieval glass in the windows.
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The author discusses long term-trends in glass production during the 1st millennium CE. The systematic application of scientific methods on archaeological finds demonstrates the complexity of glass production and the trade networks in... more
The author discusses long term-trends in glass production during the 1st millennium CE. The systematic application of scientific methods on archaeological finds demonstrates the complexity of glass production and the trade networks in glass products. Due to the limited availability of natron nearly all glass originated from Egypt and Syria-Palestine from where raw glass was distributed to secondary workshops across Eu-rope and the Near East. This mode of production remained mostly constant during Antiquity and the early Middle Ages but a long-term decline in the availability of natron led to the restructuring of production from the 9th century onwards. Der Autor bespricht Langzeittrends der Glasherstellung im 1. Jahrtausend n. Chr. Die systematische Anwendung naturwis-senschaftlicher Methoden auf archäologische Funde wird be-nutzt um die Komplexität der Produktionsketten und Han-delsnetzwerke von Glasobjekten aufzuzeigen. Wegen der be-schränkten Verfügbarkeit von Natron wird sämtliches Roh-glas aus Ägypten und der Levante in europäische Glasverar-beitungsplätze gebracht. Dieses Netzwerk bleibt während der Antike und dem Frühen Mittelalter konstant, wird aber seit dem 9. Jahrhundert strukturell anders ausgerichtet.
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Materials associated with a secondary workshop of early Byzantine date (4th-5th centuries) were unearthed in excavations by the Israel Antiquities Authority in ‘Aqir, central Israel. Fragments of furnace structure, production debris and... more
Materials associated with a secondary workshop of early Byzantine date (4th-5th centuries) were unearthed in excavations by the Israel Antiquities Authority in ‘Aqir, central Israel. Fragments of furnace structure, production debris and glass vessels have been analysed by scanning electron microscopy with energy dispersive X-ray analysis (SEM-EDS) and thin-section petrography.
The results suggest that the workshop melted raw glass chunks of similar composition to the primary glass made at Apollonia, Israel, to produce secondary glass products. Some glass vessels associated with the furnace are of different composition, and some of these may represent material brought in as cullet for recycling. The furnace was built with ceramic bricks comprising alluvial-type clay with inclusions of quartz sand, probably added as temper. It was fired by potash-rich fuel to approximately 1100°C. Lime mortar was used either to cement the gaps between mudbricks or to line the furnace as a parting layer, and it has introduced a previously unrecognised type of contamination in glass of the period, mainly of Fe2O3 and CaO. The contamination may be identified in glass vessel assemblages elsewhere but is not ubiquitous. As its origin relates to the furnace structure, its occurrence may depend upon chronology or geography and further work is needed to resolve this issue.
The results suggest that the workshop melted raw glass chunks of similar composition to the primary glass made at Apollonia, Israel, to produce secondary glass products. Some glass vessels associated with the furnace are of different composition, and some of these may represent material brought in as cullet for recycling. The furnace was built with ceramic bricks comprising alluvial-type clay with inclusions of quartz sand, probably added as temper. It was fired by potash-rich fuel to approximately 1100°C. Lime mortar was used either to cement the gaps between mudbricks or to line the furnace as a parting layer, and it has introduced a previously unrecognised type of contamination in glass of the period, mainly of Fe2O3 and CaO. The contamination may be identified in glass vessel assemblages elsewhere but is not ubiquitous. As its origin relates to the furnace structure, its occurrence may depend upon chronology or geography and further work is needed to resolve this issue.
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Archaeological glass contains information about the movement of goods and ancient economies, yet our understanding of critical aspects of the ancient glass industry is fragmentary. During Roman times, distinct glass types produced in... more
Archaeological glass contains information about the movement of goods and ancient economies, yet our understanding of critical aspects of the ancient glass industry is fragmentary. During Roman times, distinct glass types produced in coastal regions of Egypt and the Levant used evaporitic soda (natron) mixed with Nile-derived sands. In the Levant, furnaces for producing colourless Roman glass by addition of manganese have been uncovered, whereas the source of the desirable antimony-decolourised Roman glass remains an enigma. In the Edict of Diocletian, this colourless glass is listed as "Alexandrian" referring to Egypt, but its origin has been ambiguous. Previous studies have found overlapping strontium and neodymium isotope ratios for Levantine and Egyptian glass. Here, we confirm these findings and show for the first time, based on glasses from the ancient city of Gerasa, that hafnium (Hf) isotopes are different in Egyptian and Levantine natron glasses, and that Sb Roman glass is Egyptian. Our work illustrates the value of Hf isotopes in provenancing archaeological glass. We attribute the striking difference in Hf isotopes of Egyptian versus Levantine glasses to sorting of zircons in Nile sediments during longshore drift and aeolian transport along the southeastern Mediterranean coast leaving behind a less juvenile fraction. The Roman glass industry underwent a massive expansion over the first century CE. At its peak it supplied not only tablewares for households across the Empire but also furnished major public buildings with many tonnes of glass for windows and mosaics 1,2. The raw glass was made by fusing Egyptian evaporitic soda (natron) and sand to produce large glass slabs in tank furnaces with capacities of 8-20 tonnes 3,4. These were broken up and distributed to glass workshops where the glass was remelted and shaped into objects for use 5,6. This division of production continued until at least the ninth century, when a change from a mineral soda flux over to plant ash occurred bringing about the end of the Roman glassmaking tradition 7,8. The technological achievements of the Roman glass industry were precocious and not surpassed until the rise of the European industries in the eighteenth century. In particular, the Romans produced large quantities of an expensive and highly valued glass, described by Pliny 9 as "colourless or transparent, as closely as possible resembling rock crystal" (Fig. 1), where the iron from the sand was oxidised from blue Fe 2+ to very pale Fe 3+ by the addition of antimony oxide, Sb 2 O 3 10,11. In the Price Edict of Diocletian, this colourless glass is listed as "Alexandrian" thereby referring to Egypt 12. Despite this, the production site for this so-called Sb Roman glass is unknown but several authors have suggested, on the basis of circumstantial evidence, that it was in Egypt 13,14 (see Supplementary Information for details). Strong evidence that the primary glassmaking factories melting sand and natron to glass were predominantly located along the coast of the eastern Mediterranean is provided by isotopic measurements. Strontium (Sr) isotope compositions for the majority of natron glass groups are close to that of modern seawater, indicating the incorporation of marine shell in the batch and suggesting the use of beach sand as a silica source 15-17. With regards to neodymium (Nd) isotopes, nearly all natron glass types show a characteristic Nile-related signature reflecting the use of coastal sands along the southeastern Mediterranean that comprise largely Nile-derived sediments transported here by longshore drift 18,19. Hafnium (Hf) isotopes have not previously been applied to man-made archaeological material (see Supplementary Information). Here, we present Sr, Nd and Hf results on natron glass types and show that, unlike the Sr and Nd systems, hafnium isotopes distinguish between natron open
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UCL logo UCL Discovery. ...
Abstrakt: Na podstawie badań ponad 900 fragmentów średniowiecznych szkieł witrażowych, pochodzących z różnych miejsc i okresów (od XII do XVI w.), omówionych zostało kilka wybra-nych zagadnień związanych z metodyką badawczą i... more
Abstrakt: Na podstawie badań ponad 900 fragmentów średniowiecznych szkieł witrażowych, pochodzących z różnych miejsc i okresów (od XII do XVI w.), omówionych zostało kilka wybra-nych zagadnień związanych z metodyką badawczą i interpretacją wyników. Poruszona proble-matyka dotyczy dziewiętnastowiecznej restauracji witraży i ich współczesnej interpretacji, badań pojedynczej kwatery, okna i zespołu okien oraz szkieł barwnych. W ostatnim przypadku, dokład-niej zostały omówione szkła czerwone oraz dwunastowieczne szkła niebieskie, wytwarzane przy użyciu rzymskich tesserae. Słowa kluczowe: szkło, witraż, średniowiecze, archeometria szkła, SEM-EDS, LA ICP MS, mikro-skopia optyczna, konserwacja i restauracja. Abstract: Research on more than 900 fragments of medieval stained glass from different places and periods (from the 12 th
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Copyright © Centre for Byzantine Cultural History 2009
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Palestine and Egypt supplied the Mediterranean and Europe with virtually all of its glass for most of the first millennium CE. While the Muslim conquest in the 7th century saw major political and economic adjustment, immediate changes to... more
Palestine and Egypt supplied the Mediterranean and Europe with virtually all of its glass for most of the first millennium CE. While the Muslim conquest in the 7th century saw major political and economic adjustment, immediate changes to material culture appear to have been minimal. This paper examines the impact of the Byzantine-Islamic transition on the natron glass industry of Palestine from the 7th to 12th century. A series of 133 well-contextualised glass vessels from selected excavations in modern day Israel have been analysed for major, minor and trace elements using LA-ICP-MS. These glasses are assigned to previously established primary production groups, allowing the elucidation of the chronology of key changes in glass production in the region. Results indicate a relatively abrupt compostional change in the late 7th-early 8th centuries, covering the reforming reigns of al-Malik and al-Walid, which marks the end of " Byzantine " glass production and the establishment of the furnaces at Bet Eli'ezer. At about this time there was an influx of glass of an Egyptian composition. Production of Bet Eli'ezer type glass appears to have been limited to a short time span, less than 50 years, after which natron glass production in Palestine ceased. Plant ash glass is first encountered in the late 8th-early 9th century, probably as a result of reduced local natron glass production creating the conditions in which plant ash glass technology was adopted. Egypt continued to produce natron glass for up to a century after its demise in Palestine. It is reasoned that the change and then collapse in natron glass production in Palestine may well have been as a consequence of a reduction in the quantities of available natron. This affected Palestine first, and Egypt up to 100 years later, which suggests that the factors causing the reduction in natron supply originated at the source and were long term and gradual, not short term events.
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Jointly authored paper with I.C. Freestone, J.C. Ambers and M. as-Sayyani.
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Page 1. Introduction The chemical composition of Anglo-Saxon glass has been the subject of a number of published studies over the past three decades (eg Sanderson et al. 1984; Henderson 1993b; Hunter and Heyworth 1998 ...
... 5); the chlorine probably derived from the mineral salts used to supply the alkali during the ... wrote in the early fourth century AD, reports a letter supposedly written by Hadrian to his ... vessels that change colour were being... more
... 5); the chlorine probably derived from the mineral salts used to supply the alkali during the ... wrote in the early fourth century AD, reports a letter supposedly written by Hadrian to his ... vessels that change colour were being made in the early fourth century (Vopiscus had seen them ...
Close Document Image Close Document Printer Image Print This Document! Conservation Information Network (BCIN). Author: Freestone, Ian C. Editor: Bimson, M.; Freestone, IC Title Article/Chapter: "Composition and microstructure ...
... Was all Roman glass imported?: Ian Reestone of the British Museum describes how science is throwing new light on ghe study of glass. Autores: Ian Freestone; Localización: Current archaeology, ISSN 0011-3212, Nº 186, 2003 , págs.... more
... Was all Roman glass imported?: Ian Reestone of the British Museum describes how science is throwing new light on ghe study of glass. Autores: Ian Freestone; Localización: Current archaeology, ISSN 0011-3212, Nº 186, 2003 , págs. 258-260. Fundación Dialnet. ...
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An Egyptian glass scarab (1891,0509.35: EA 22872), previously thought to be from the New Kingdom period, was found upon conservation to be weeping. Analysis of the glass showed it to be of an unstable composition with high soda and low... more
An Egyptian glass scarab (1891,0509.35: EA 22872), previously thought to be from the New Kingdom period, was found upon conservation to be weeping. Analysis of the glass showed it to be of an unstable composition with high soda and low lime concentrations. Th e composition is similar to rare items found in the tomb of Nesikhons dating to the Th ird Intermediate Period. Th e weeping salts were found to be predominantly sodium formate (methanoate) produced as a result of off gassing from the storage environment. The analysis and conservation of the scarab are described and recommendations made for future storage of the object. http://www.britishmuseum.org/pdf/BMTRB%202%20Fletcher.pdf
ABSTRACTCurrent understanding of medieval glass composition is compared with the instructions for the preparation and use of glass outlined by Theophilus in the early twelfth century. The points are illustrated by analyses of glasses from... more
ABSTRACTCurrent understanding of medieval glass composition is compared with the instructions for the preparation and use of glass outlined by Theophilus in the early twelfth century. The points are illustrated by analyses of glasses from a range of objects and locations. They include the Westminster Retable, the pavement at Cluny Cathedral, Romanesque Mosan enamels on copper, Abbey windows from San Vincenzo in Italy and early enamelled glass vessels which are likely to have been made in Venice.
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Isotopic composition of glass from the Levant and the south-eastern Mediterranean Region Isotopic composition of glass from the Levant and the south-eastern Mediterranean Region Ian C. Freestone, Sophie Wolf, Matthew Thirlwall Ian C.... more
Isotopic composition of glass from the Levant and the south-eastern Mediterranean Region Isotopic composition of glass from the Levant and the south-eastern Mediterranean Region Ian C. Freestone, Sophie Wolf, Matthew Thirlwall Ian C. Freestone, Sophie Wolf, Matthew ...
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A materials science approach can illuminate our understanding of the life history of medieval stained glass windows; however, chemical analysis has been inhibited by their architectural context, preventing the removal of samples.... more
A materials science approach can illuminate our understanding of the life history of medieval stained glass windows; however, chemical analysis has been inhibited by their architectural context, preventing the removal of samples. Non-invasive techniques that can be used in situ, such as handheld/portable X-ray fluorescence spectrometry (pXRF), are thus very important to this field of study, yet this technique is also impeded by significant obstacles: the presence of deterioration and painted detail (subject of a previous paper) and the protrusion of the lead cames which hold the individual pieces together. In the present paper, we address the obstacle that lead cames present for in situ analysis and offer a simple, inexpensive and adaptable solution in the form of a 3D-printed attachment (a window analyzer, or "WindoLyzer") that allows control over the working distance between spectrometer and sample. This simple modification to the standard pXRF system combined with empirical calibrations allows precise, reproducible results with a level of accuracy sufficient to distinguish compositional groups. We then present a case study in which this development is put to practice to answer important questions related to the history of conservation of a medieval panel from Canterbury Cathedral. This technique has allowed the recognition of previously unidentified repairs to the original panel, and shown that late eighteenth century craftsmen were recycling medieval glass to execute their work. Particularly promising is the ability to distinguish different groups of glass which are clearly of medieval origin, opening the way for future studies on the movement of glass in the medieval period.
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Archaeological glass contains information about the movement of goods and ancient economies, yet our understanding of critical aspects of the ancient glass industry is fragmentary. During Roman times, distinct glass types produced in... more
Archaeological glass contains information about the movement of goods and ancient economies, yet our understanding of critical aspects of the ancient glass industry is fragmentary. During Roman times, distinct glass types produced in coastal regions of Egypt and the Levant used evaporitic soda (natron) mixed with Nile-derived sands. In the Levant, furnaces for producing colourless Roman glass by addition of manganese have been uncovered, whereas the source of the desirable antimony-decolourised Roman glass remains an enigma. In the Edict of Diocletian, this colourless glass is listed as "Alexandrian" referring to Egypt, but its origin has been ambiguous. Previous studies have found overlapping strontium and neodymium isotope ratios for Levantine and Egyptian glass. Here, we confirm these findings and show for the first time, based on glasses from the ancient city of Gerasa, that hafnium (Hf) isotopes are different in Egyptian and Levantine natron glasses, and that Sb Roman glass is Egyptian. Our work illustrates the value of Hf isotopes in provenancing archaeological glass. We attribute the striking difference in Hf isotopes of Egyptian versus Levantine glasses to sorting of zircons in Nile sediments during longshore drift and aeolian transport along the southeastern Mediterranean coast leaving behind a less juvenile fraction. The Roman glass industry underwent a massive expansion over the first century CE. At its peak it supplied not only tablewares for households across the Empire but also furnished major public buildings with many tonnes of glass for windows and mosaics 1,2. The raw glass was made by fusing Egyptian evaporitic soda (natron) and sand to produce large glass slabs in tank furnaces with capacities of 8-20 tonnes 3,4. These were broken up and distributed to glass workshops where the glass was remelted and shaped into objects for use 5,6. This division of production continued until at least the ninth century, when a change from a mineral soda flux over to plant ash occurred bringing about the end of the Roman glassmaking tradition 7,8. The technological achievements of the Roman glass industry were precocious and not surpassed until the rise of the European industries in the eighteenth century. In particular, the Romans produced large quantities of an expensive and highly valued glass, described by Pliny 9 as "colourless or transparent, as closely as possible resembling rock crystal" (Fig. 1), where the iron from the sand was oxidised from blue Fe 2+ to very pale Fe 3+ by the addition of antimony oxide, Sb 2 O 3 10,11. In the Price Edict of Diocletian, this colourless glass is listed as "Alexandrian" thereby referring to Egypt 12. Despite this, the production site for this so-called Sb Roman glass is unknown but several authors have suggested, on the basis of circumstantial evidence, that it was in Egypt 13,14 (see Supplementary Information for details). Strong evidence that the primary glassmaking factories melting sand and natron to glass were predominantly located along the coast of the eastern Mediterranean is provided by isotopic measurements. Strontium (Sr) isotope compositions for the majority of natron glass groups are close to that of modern seawater, indicating the incorporation of marine shell in the batch and suggesting the use of beach sand as a silica source 15-17. With regards to neodymium (Nd) isotopes, nearly all natron glass types show a characteristic Nile-related signature reflecting the use of coastal sands along the southeastern Mediterranean that comprise largely Nile-derived sediments transported here by longshore drift 18,19. Hafnium (Hf) isotopes have not previously been applied to man-made archaeological material (see Supplementary Information). Here, we present Sr, Nd and Hf results on natron glass types and show that, unlike the Sr and Nd systems, hafnium isotopes distinguish between natron open
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New elemental data confirm the proposal by Ceglia et al. (2015) of two sub-groups of high iron, manganese and titanium glass, HIMTa and HIMTb, differing in their ratios Fe2O3/TiO2 and Fe2O3/Al2O3. Neodymium and strontium isotopes are... more
New elemental data confirm the proposal by Ceglia et al. (2015) of two sub-groups of high iron, manganese and titanium glass, HIMTa and HIMTb, differing in their ratios Fe2O3/TiO2 and Fe2O3/Al2O3. Neodymium and strontium isotopes are consistent with southeastern Mediterranean coastal sand for both groups, allowing for an identifiable strontium contribution from the added manganese. Trace elements are consistent with an Egyptian origin, although a marked Eu anomaly in HIMTa is correlated with Ba, again added with manganese. Strong within group correlations between manganese and iron oxides are not easily explained either as deliberate additions of manganese decolouriser or as a characteristic of the glassmaking sand. Instead, HIMT glass is considered to have been deliberately tinted yellow-green by the primary glassmakers to distinguish it from the green-blue glass of the Levant. The colour branding of the raw glass allowed glass workers to distinguish sodium-rich Egyptian HIMT glass from the more viscous, high working temperature Levantine glass, thereby offering savings in marginal costs, such as those relating to fuel.
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Chapters by Peltenburg; Reade; Tite Bimson and Cowell; Caubet and Kaczmarczyk; Foster; Mazzoni; Vandiver and Kingery
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Chapters by McGovern; Holbl; Tite Bimson and Freestone; Kleinmann; Webb; Cable and Smedley; Bimson; Freestone
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The gems on a thirteenth-century reliquary of St Eustace have been examined nondestructively using Raman microspectroscopy with a horizontal laser attachment and X-ray fluorescence spectrometry. Nine of the gems are composed of varieties... more
The gems on a thirteenth-century reliquary of St Eustace have been examined nondestructively using Raman microspectroscopy with a horizontal laser attachment and X-ray fluorescence spectrometry. Nine of the gems are composed of varieties of quartz (rock crystal, chalcedony, amethyst and carnelian), two of aragonite (pearl and mother of pearl), one of obsidian and six of synthetic glass. The compositions of five glass stones suggest that they represent re-used Roman glass, while the intaglio on the obsidian and a drill hole in the pearl also suggest the re-use of old material. One glass stone has a medieval glass composition.
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Twenty-two objects of glass from the Decapolis city of Gerasa, N. Jordan, with characteristic vessel forms ranging from Hellenistic to Early Islamic (2nd century BCE to 8th century CE) were analyzed for major and trace elements, and 16... more
Twenty-two objects of glass from the Decapolis city of Gerasa, N. Jordan, with characteristic vessel forms ranging from Hellenistic to Early Islamic (2nd century BCE to 8th century CE) were analyzed for major and trace elements, and 16 samples for Sr-isotopes. The majority were produced in the vicinity of Apollonia on the Palestine coast in the 6th–7th centuries CE, and strong inter-element correlations for Fe, Ti, Mn, Mg, Nb reflect local variations in the accessory minerals in the Apollonia glassmaking sand. The ubiquity of recycling is reflected in elevated concentrations and high coefficients of variation of colorant-related elements as well as a strong positive correlation between K and P. The high level of K contamination is attributed to the use of pomace (olive processing residue) as fuel, and a negative correlation with Cl, due to volatilization as the glass was reheated. This points to an efficient system for the collection of glass for recycling in Jerash during the latter part of the first millennium CE. Differences in elemental behavior at different sites in the Levant may reflect the context of the recycling system, for example, glass from secular contexts may contain less colorants derived from mosaics than glass associated with churches.
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The surfaces of 30 pieces of glass from panel 3b of the Great East Window of York Minster (1405-1408 CE) were analyzed by handheld portable x-ray fluorescence (pXRF) and small samples from the same pieces were analyzed by electron... more
The surfaces of 30 pieces of glass from panel 3b of the Great East Window of York Minster (1405-1408 CE) were analyzed by handheld portable x-ray fluorescence (pXRF) and small samples from the same pieces were analyzed by electron microprobe (EPMA). Comparison of the two methods reveals significant divergences which are not systematic, particularly for elements lighter than Ti. Rather than a problem with pXRF calibration or correction software, the non-systematic error is attributable to the presence of a thin surface layer of weathered glass. Analysis of the depths of X-ray generation indicate that virtually all x-rays characteristic of Ca and K are generated within the top 50 µm of the glass. However, for heavier elements such as Rb, Sr and Zr, most emitted X-rays are generated below 100 µm. Using pXRF data for the heavier elements, it is possible to replicate the compositional groupings identified by quantitative EPMA. White glass in the window is likely to have originated in England, while colored glasses were probably obtained from the Continent. The alkali contents of the green and yellow glasses appear to have been manipulated to generate their colors. Glass which is medieval in technology but not original to the panel was identified. In particular, zirconium proved a useful indicator of glassmaking regions, and rubidium and strontium were more sensitive to differences between batches, which has interesting implications for future work.
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An assemblage of glassy materials from Culduthel, an Iron Age site in Northeast Scotland, mainly comprises fragments and beads of just a few millimetres in size and is unique in the region. The glasses were analysed by scanning electron... more
An assemblage of glassy materials from Culduthel, an Iron Age site in Northeast Scotland, mainly comprises fragments and beads of just a few millimetres in size and is unique in the region. The glasses were analysed by scanning electron microscopy-energy dispersive X-ray analysis. Opaque red glass comprises mainly droplets and fragments, is typical of the late Iron Age and may have been used to manufacture inlay in copper alloy metalwork recovered from the site. Compositional characteristics of the red suggest that it was derived from a single block or ingot. Opaque yellow occurs mainly as beads and antimony- and lesser amounts of tin-opacified glass are present. Evidence for the melting of antimony-opacified yellow glass occurs in a composite fragment of opaque red, yellow and colourless glass and may reflect the manufacture of beads. Blue glass is less abundant and more variable in composition, it is likely to have been acquired over a longer period. The base glass for the majority of samples is the high-lime high-alumina manganese-decolourised variety, typical of the Hellenistic and early Roman periods and originating in the Levant. The absence of low-lime, low-alumina antimony-decolourised Roman glass from the assemblage indicates an original date of manufacture before the middle of the first century CE.
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Detailed studies of the pottery and stuccoes of the church and associated complex at Sir Bani Yas indicate these date to the seventh and eighth centuries. This paper examines the only other significant set of finds, namely the glassware.... more
Detailed studies of the pottery and stuccoes of the church and associated complex at Sir Bani Yas indicate these date to the seventh and eighth centuries. This paper examines the only other significant set of finds, namely the glassware. Several other churches and monasteries have been excavated in the Persian Gulf and Western Desert of Iraq but this is the first occasion where the glass assemblage has been studied in detail and has included comprehensive scientific analysis of the glass compositions. Analysis by electron probe microanalysis of 85 samples with multi-variate statistical analysis has identified four compositional groups of plant ash glass. The largest is relatively high in lime and alumina, and could not be related to previously analysed groups. Two groups were compositionally similar to Mesopotamian glass of the Sasanian and early Islamic periods, corresponding to Mesopotamian Types 1 and 2 of Phelps (2016, 2018) and suggest trade in glass from Mesopotamia to Sir Bani Yas. A final group is small and shares similarity to three contemporary samples from Kush. The sparse use of MnO as a decolourant in the glass as opposed to its ubiquitous use in 9 th century Abbasid glass suggests an Early Islamic seventh-eighth century date for this assemblage, consistent with the ceramic dating.
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Twenty glass samples collected from four structures at Umm el-Jimal, northeast Jordan were analysed using the electron probe microanalysis (EPMA). Except one ash-soda-lime-silica glass, all were natron soda-lime-silica glasses of... more
Twenty glass samples collected from four structures at Umm el-Jimal, northeast Jordan were analysed using the electron probe microanalysis (EPMA). Except one ash-soda-lime-silica glass, all were natron soda-lime-silica glasses of Levantine origin. Most of the glasses compositionally resemble glass from the Byzantine tank furnaces at Apollonia-Arsuf (Arsuf), but four with lower lime are closer to Umayyad period production at Bet Eli’ezer (Hadera). The paper presents diagnostic information indicating recycling in a diagnostic recycling table (DRT) in which the analyses are ranked in a descending order of K2O, a key contaminant in the recycling process. This allows the comparison of a range of contaminant elements and it is observed that in general glass contaminated with fuel ash components K2O, P2O5 and CaO are also richer in transition metal oxides CuO, PbO, FeO and MnO, confirming that both sets of elements are important in identifying recycled glass. Chlorine is also identified as a component modified by recycling. The results ascertain that Umm el-Jimal was part of a major system of glass recycling in the Byzantine period, and emphasise the importance of recycled glass in its supply, in spite of its relative proximity to the location of raw glass production on the Syro-Palestinian coast.
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Palestine and Egypt supplied the Mediterranean and Europe with virtually all of its glass for most of the first millennium CE. While the Muslim conquest in the 7th century saw major political and economic adjustment, immediate changes to... more
Palestine and Egypt supplied the Mediterranean and Europe with virtually all of its glass for most of the first millennium CE. While the Muslim conquest in the 7th century saw major political and economic
adjustment, immediate changes to material culture appear to have been minimal. This paper examines the impact of the Byzantine-Islamic transition on the natron glass industry of Palestine from the 7th to
12th century. A series of 133 well-contextualised glass vessels from selected excavations in modern day Israel have been analysed for major, minor and trace elements using LA-ICP-MS. These glasses are assigned to previously established primary production groups, allowing the elucidation of the chronology of key changes in glass production in the region. Results indicate a relatively abrupt compositional change in the late 7th - early 8th centuries, covering the reforming reigns of al-Malik and al-Walid, which marks the end of “Byzantine” glass production and the establishment of the furnaces at Bet Eli'ezer. At about this time there was an influx of glass of an Egyptian composition. Production of Bet Eli'ezer type glass appears to have been limited to a short time span, less than 50 years, after which natron glass production in Palestine ceased. Plant ash glass is first encountered in the late 8th-early 9th century, probably as a result of reduced local natron glass production creating the conditions in which plant ash glass technology was adopted. Egypt continued to produce natron glass for up to a century after its demise in Palestine. It is reasoned that the change and then collapse in natron glass production in Palestine may well have been as a consequence of a reduction in the quantities of available natron. This affected Palestine first, and Egypt up to 100 years later, which suggests that the factors causing the reduction in natron supply originated at the source and were long term and gradual, not short term
events.
adjustment, immediate changes to material culture appear to have been minimal. This paper examines the impact of the Byzantine-Islamic transition on the natron glass industry of Palestine from the 7th to
12th century. A series of 133 well-contextualised glass vessels from selected excavations in modern day Israel have been analysed for major, minor and trace elements using LA-ICP-MS. These glasses are assigned to previously established primary production groups, allowing the elucidation of the chronology of key changes in glass production in the region. Results indicate a relatively abrupt compositional change in the late 7th - early 8th centuries, covering the reforming reigns of al-Malik and al-Walid, which marks the end of “Byzantine” glass production and the establishment of the furnaces at Bet Eli'ezer. At about this time there was an influx of glass of an Egyptian composition. Production of Bet Eli'ezer type glass appears to have been limited to a short time span, less than 50 years, after which natron glass production in Palestine ceased. Plant ash glass is first encountered in the late 8th-early 9th century, probably as a result of reduced local natron glass production creating the conditions in which plant ash glass technology was adopted. Egypt continued to produce natron glass for up to a century after its demise in Palestine. It is reasoned that the change and then collapse in natron glass production in Palestine may well have been as a consequence of a reduction in the quantities of available natron. This affected Palestine first, and Egypt up to 100 years later, which suggests that the factors causing the reduction in natron supply originated at the source and were long term and gradual, not short term
events.
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Carthage played an important role in maritime exchange networks during the Roman and late antique periods. One hundred ten glass fragments dating to the third to sixth centuries CE from a secondary deposit at the Yasmina Necropolis in... more
Carthage played an important role in maritime exchange networks during the Roman and late antique periods. One hundred ten glass fragments dating to the third to sixth centuries CE from a secondary deposit at the Yasmina Necropolis in Carthage have been analysed by electron micro-probe analysis (EPMA) to characterise the supply of glass to the city. Detailed bivariate and multivariate data analysis identified different primary glass groups and revealed evidence of extensive recycling. Roman mixed antimony and manganese glasses with MnO contents in excess of 250 ppm were clearly the product of recycling, while iron, potassium and phosphorus oxides were frequent contaminants. Primary glass sources were discriminated using TiO 2 as a proxy for heavy minerals (ilmenite/spinel), Al 2 O 3 for feldspar and SiO 2 for quartz in the glassmaking sands. It was thus possible to draw conclusions about the chronological and geographical attributions of the primary glass types. Throughout much of the period covered in this study, glassworkers in Carthage utilised glass from both Egyptian and Levantine sources. Based on their geochemical characteristics, we conclude that Roman antimony and Roman manganese glasses originated from Egypt and the Levant, respectively, and were more or less simultaneously worked at Carthage in the fourth century as attested by their mixed recycling (Roman Sb-Mn). In the later fourth and early fifth centuries, glasses from Egypt (HIMT) and the Levant (two Levantine I groups) continued to be imported to Carthage, although the Egyptian HIMT is less well represented at Yasmina than in many other late antique glass assemblages. In contrast, in the later fifth and sixth centuries, glass seems to have been almost exclusively sourced from Egypt in the form of a manganese-decolourised glass originally described and characterised by Foy and colleagues (2003). Hence, the Yasmina assemblage testifies to significant fluctuations in the supply of glass to Carthage that require further attention.
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Excavations in the upper Walbrook valley, in a marginal area in the north-west of the Roman city, recovered over 70kg of broken vessel glass and production waste from a nearby workshop, giving new insights into the workings of the glass... more
Excavations in the upper Walbrook valley, in a marginal area in the north-west of the Roman city, recovered over 70kg of broken vessel glass and production waste from a nearby workshop, giving new insights into the workings of the glass industry and its craftsmen. The area was developed in the early 2nd century AD, with evidence of domestic buildings and property boundaries. Two later buildings constructed in the mid 2nd century AD may have been associated with the glass-working industry. The disposal of a huge amount of glass-working waste in the later 2nd century signals the demise of the workshop, with the area reverting to open land by the 3rd century AD. The comprehensive nature of the glass-working waste has made it possible to study the various processes from the preparation of the raw materials in the form of cullet, broken vessel and window glass, to the blowing and finishing of the vessel. All the glass originated ultimately in the eastern Mediterranean, some of it arriving as raw glass chunks, which was supplemented by cullet collected locally for recycling. A review of the current evidence for glass working in London also examines the implications for the organisation of the industry
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Provides interpretation of the glass on the basis of major and trace elements and Sr and Nd isotopes
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Research over the last few decades has greatly enhanced our understanding of the production and distribution of glass across time and space, resulting in an almost kaleidoscopically colourful and complex picture. We now recognise several... more
Research over the last few decades has greatly enhanced our understanding of the production and distribution of glass across time and space, resulting in an almost kaleidoscopically colourful and complex picture. We now recognise several major ‘families’ of glass composition, including plant-ash based glass in Late Bronze Age Egypt and Mesopotamia, and the Islamic World; mineral natron glass in the Greek, Roman and Byzantine Empires; mineral-based lead- and lead-barium glass in Han period China and medieval Europe; and wood-ash and ash-lime glass in medieval Europe. Other glass groups include a peculiar granite-based glass in medieval Nigeria, and probably mineral-based glass in Bronze Age southern Europe. However, despite two centuries of research, we know very little about the actual production locations and technologies for most of these glass groups, and how and where glass making was invented.
The early literature reflects the comparatively limited number of individuals and research groups working on glass; only recently there is a significant broadening of the research community and expansion and refinement of the data base. This enables us now to take stock of our current understanding and identify major lacunae and areas where additional work may make the most significant contributions to our understanding of the complex picture. Hopefully this will help moving from the traditional descriptive and often fragmented opportunistic data-gathering phase (asking ‘what’, ‘where’ and ‘when’) to a more interpretative period looking with fresh eyes at the ‘why’ and ‘how’ of compositional and technical developments. This opening of the research field includes addressing the relationship of the different glass industries to the societies that used glass, and how they organised its production and distribution. A major overarching issue remains the question of the initial invention of glass, and how the idea as well as the material itself spread. Major debates should ask whether there were multiple inventions of glass making; how best to identify and interpret long-distance trade; how to ensure data compatibility and quality; and how to integrate different types of data, from archaeology through craftsmanship and typology to chemistry and optical properties.
The early literature reflects the comparatively limited number of individuals and research groups working on glass; only recently there is a significant broadening of the research community and expansion and refinement of the data base. This enables us now to take stock of our current understanding and identify major lacunae and areas where additional work may make the most significant contributions to our understanding of the complex picture. Hopefully this will help moving from the traditional descriptive and often fragmented opportunistic data-gathering phase (asking ‘what’, ‘where’ and ‘when’) to a more interpretative period looking with fresh eyes at the ‘why’ and ‘how’ of compositional and technical developments. This opening of the research field includes addressing the relationship of the different glass industries to the societies that used glass, and how they organised its production and distribution. A major overarching issue remains the question of the initial invention of glass, and how the idea as well as the material itself spread. Major debates should ask whether there were multiple inventions of glass making; how best to identify and interpret long-distance trade; how to ensure data compatibility and quality; and how to integrate different types of data, from archaeology through craftsmanship and typology to chemistry and optical properties.
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Schibille N, Freestone IC (2013) Composition, Production and Procurement of Glass at San Vincenzo al Volturno: An Early Medieval Monastic Complex in Southern Italy. PLoS ONE 8(10): e76479. doi:10.1371/journal.pone.0076479 136 glasses... more
Schibille N, Freestone IC (2013) Composition, Production and Procurement of Glass at San Vincenzo al Volturno: An Early Medieval Monastic Complex in
Southern Italy. PLoS ONE 8(10): e76479. doi:10.1371/journal.pone.0076479
136 glasses from the ninth-century monastery of San Vincenzo and its workshops have been analysed by electron microprobe in order to situate the assemblage within the first millennium CE glass making tradition. The majority of the glass compositions can be paralleled by Roman glass from the first to third centuries, with very few samples consistent with later compositional groups. Colours for trailed decoration on vessels, for vessel bodies and for sheet glass for windows were largely produced by melting the glass tesserae from old Roman mosaics. Some weakly-coloured transparent glass was obtained by re-melting Roman window glass, while some was produced by melting and mixing of tesserae, excluding the strongly coloured cobalt blues. Our data suggest that to feed the needs of the glass workshop, the bulk of the glass was removed as tesserae and windows from a large Roman building. This is consistent with a historical account according to which the granite columns of the monastic church were spolia from a Roman temple in the region. The purported shortage of natron from Egypt does not appear to explain the dependency of San Vincenzo on old Roman glass. Rather, the absence of contemporary primary glass may reflect the downturn in long-distance trade in the later first millennium C.E., and the role of patronage in the “ritual economy” founded upon donations and gift-giving of the time
Southern Italy. PLoS ONE 8(10): e76479. doi:10.1371/journal.pone.0076479
136 glasses from the ninth-century monastery of San Vincenzo and its workshops have been analysed by electron microprobe in order to situate the assemblage within the first millennium CE glass making tradition. The majority of the glass compositions can be paralleled by Roman glass from the first to third centuries, with very few samples consistent with later compositional groups. Colours for trailed decoration on vessels, for vessel bodies and for sheet glass for windows were largely produced by melting the glass tesserae from old Roman mosaics. Some weakly-coloured transparent glass was obtained by re-melting Roman window glass, while some was produced by melting and mixing of tesserae, excluding the strongly coloured cobalt blues. Our data suggest that to feed the needs of the glass workshop, the bulk of the glass was removed as tesserae and windows from a large Roman building. This is consistent with a historical account according to which the granite columns of the monastic church were spolia from a Roman temple in the region. The purported shortage of natron from Egypt does not appear to explain the dependency of San Vincenzo on old Roman glass. Rather, the absence of contemporary primary glass may reflect the downturn in long-distance trade in the later first millennium C.E., and the role of patronage in the “ritual economy” founded upon donations and gift-giving of the time
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Abstract: The 18 articles arising from a one-day seminar at the British Museum in 1987 cover Europe, the Mediterranean, the Near East, North Africa, and the New World. Chronologically, the ceramic materials range from the 7th millennium... more
Abstract: The 18 articles arising from a one-day seminar at the British Museum in 1987 cover Europe, the Mediterranean, the Near East, North Africa, and the New World. Chronologically, the ceramic materials range from the 7th millennium BC to the 16th ...
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Close Document Image Close Document Printer Image Print This Document! Conservation Information Network (BCIN). Author: Freestone, Ian C. Editor: Middleton, Andrew; Freestone, Ian C. Title Article/Chapter: "Extending ...
ABSTRACT
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... The best preserved colour is black, which appears glossy on some plaques, but even so is iridescent. The white glaze is matt but coherent, while the yellow and greenish glazes are very poorly preserved. ... detail by Fitz (1983), who... more
... The best preserved colour is black, which appears glossy on some plaques, but even so is iridescent. The white glaze is matt but coherent, while the yellow and greenish glazes are very poorly preserved. ... detail by Fitz (1983), who carried out semi-quantitative ...
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... A locally produced group of faience appears to have a glaze formed by the direct application of the glaze mixture. ... may be of mixed provenance, while the microstructure of a third group of material imported from Egypt suggests the... more
... A locally produced group of faience appears to have a glaze formed by the direct application of the glaze mixture. ... may be of mixed provenance, while the microstructure of a third group of material imported from Egypt suggests the use of the cementation method of glazing. ...
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The suggestion by Armstrong (2020) that the ceramics from the fifth century monastery of St. Lot, Jordan, represent evidence for an early Byzantine alkali glazing tradition is based upon a misinterpretation of an earlier study by... more
The suggestion by Armstrong (2020) that the ceramics from the fifth century monastery of St. Lot, Jordan,
represent evidence for an early Byzantine alkali glazing tradition is based upon a misinterpretation of an earlier study by Freestone et al. (2001). The St. Lot glazes were unintentional and formed as a result of the reaction of the kiln vapour with the clay ceramic. Evidence for an early Byzantine alkali glazing technology is called into question.
represent evidence for an early Byzantine alkali glazing tradition is based upon a misinterpretation of an earlier study by Freestone et al. (2001). The St. Lot glazes were unintentional and formed as a result of the reaction of the kiln vapour with the clay ceramic. Evidence for an early Byzantine alkali glazing technology is called into question.
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Celadon, technically a stoneware with a lime-rich glaze, had been produced in South China for more than two millennia before it was first made in the North in the second half of the sixth century. It appears to have been an immediate... more
Celadon, technically a stoneware with a lime-rich glaze, had been produced in South China for more than two millennia before it was first made in the North in the second half of the sixth century. It appears to have been an immediate precursor to white porcelain, which was first produced by northern kilns. The compositions and microstructures of early northern celadons from kilns, residential sites and tombs in handong, Hebei and Henan provinces, and dated 550s-618 CE, have een determined by SEM-EDS. The majority of the vessels were made using a low-iron kaolinitic clay, with high alumina (20–29%), as anticipated for northern clays. A small number of celadon vessels from a kiln at Caocun, which produced mainly lead-glazed wares, have lower alumina contents and appear to have originated in the South. It seems possible that these imported vessels were being used by the potters as models on which Caocun wares were based. Consistent differences in major element composition are observed between the products of kilns at Anyang, Xing, Luoyang and Zhaili. Unlike southern celadon glazes,
which were prepared as two-component mixtures of vegetal ash and body clay, the northern celadon glazes are three-component, and typically contained an additional siliceous component, probably loess. An exception is the glazes of the Xing celadons, which present no evidence for loess but which are rich in Na2O. The source of the
soda is unclear, common salt and albitic feldspar are discussed as possibilities. Based upon micromorphological characteristics such as the relative size and abundance of remnant quartz and the extent of observable mullite, as well as the position of the glazes in the CaO-Al2O3-SiO2 phase diagram, the Xing bodies are more mature and they
appear to have been fired to higher temperatures than the products of other kilns. These results suggest that celadon technology was not directly transferred to the North from the South, but that the northern potters adopted their own strategies to make high-fired glazes. Furthermore, each kiln appears to have had its own preferred recipe, to suit the available raw materials. The products of Xing kiln were exceptional and it appears that here the trajectory towards white porcelain was already apparent, perhaps reflecting the creativity of the
Xing potters who were among the first to make a successful white porcelain.
which were prepared as two-component mixtures of vegetal ash and body clay, the northern celadon glazes are three-component, and typically contained an additional siliceous component, probably loess. An exception is the glazes of the Xing celadons, which present no evidence for loess but which are rich in Na2O. The source of the
soda is unclear, common salt and albitic feldspar are discussed as possibilities. Based upon micromorphological characteristics such as the relative size and abundance of remnant quartz and the extent of observable mullite, as well as the position of the glazes in the CaO-Al2O3-SiO2 phase diagram, the Xing bodies are more mature and they
appear to have been fired to higher temperatures than the products of other kilns. These results suggest that celadon technology was not directly transferred to the North from the South, but that the northern potters adopted their own strategies to make high-fired glazes. Furthermore, each kiln appears to have had its own preferred recipe, to suit the available raw materials. The products of Xing kiln were exceptional and it appears that here the trajectory towards white porcelain was already apparent, perhaps reflecting the creativity of the
Xing potters who were among the first to make a successful white porcelain.
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Front material plus papers by: Allen; Barnett; Betts; Echallier; Fieller and Nicholson
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Papers by Vaughan; Whitbread; Williams and Arthur; Freestone
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Papers by: Morris; Peacock and Tomber; Sheridan
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Papers by Mason; Matthew, Wood and Oliver; Middleton, Leese and Cowell
Papers by Gerrard and Gutierrez; Ixer and Lunt; Jones
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Proceedings of a Conference on ceramics held in the British Museum in November 1987 Part 1: papers by Allen, Barnett, Betts, Echallier, Fieller/Nicholson Part 2: Papers by Gerrard/Gutierrez, Ixer/Lunt, Jones Part 3: Papers by Mason,... more
Proceedings of a Conference on ceramics held in the British Museum in November 1987
Part 1: papers by Allen, Barnett, Betts, Echallier, Fieller/Nicholson
Part 2: Papers by Gerrard/Gutierrez, Ixer/Lunt, Jones
Part 3: Papers by Mason, Mattehw/Woods/Oliver
Part 4: Papers by: Middleton/Leese/Cowell, Morris, Peacock/Tomber, Sheridan
Part 5: Papers by Vaughan, Whitbread, Williams/Arthur, Freestone
Part 1: papers by Allen, Barnett, Betts, Echallier, Fieller/Nicholson
Part 2: Papers by Gerrard/Gutierrez, Ixer/Lunt, Jones
Part 3: Papers by Mason, Mattehw/Woods/Oliver
Part 4: Papers by: Middleton/Leese/Cowell, Morris, Peacock/Tomber, Sheridan
Part 5: Papers by Vaughan, Whitbread, Williams/Arthur, Freestone
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registration for the upcoming Early High-Technology Ceramics Meeting is open http://bit.ly/2nzsr8V! There are a range of excellent papers on the schedule (see list of titles and authors below - N.B. not in running order) for the 27th... more
registration for the upcoming Early High-Technology Ceramics Meeting is open http://bit.ly/2nzsr8V! There are a range of excellent papers on the schedule (see list of titles and authors below - N.B. not in running order) for the 27th April 2017 and we look forward to welcoming you to the Institute once again.
Registration is open till the 20th April but early registration is recommended as we are a little more limited on space this year. The cost of registration will be £10 (to cover lunch and refreshments) and we will collect this at registration on the day.
Registration is open till the 20th April but early registration is recommended as we are a little more limited on space this year. The cost of registration will be £10 (to cover lunch and refreshments) and we will collect this at registration on the day.
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Chinese Yue wares and Korean celadon wares are the products of two famous East Asian stoneware traditions. The Korean wares were inspired by Chinese Yue wares, but have much finer glazes. Chemical analysis and geological data suggest that... more
Chinese Yue wares and Korean celadon wares are the products of two famous East Asian stoneware traditions. The Korean wares were inspired by Chinese Yue wares, but have much finer glazes. Chemical analysis and geological data suggest that the Yue ware ...
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... Comparison of composition and microstructure of the white stoneware with that of Chinese and European porcelain indicates that Dwight fairly closely reproduced Chinese porcelain bodies, but because he did not use a lime-alkali slip... more
... Comparison of composition and microstructure of the white stoneware with that of Chinese and European porcelain indicates that Dwight fairly closely reproduced Chinese porcelain bodies, but because he did not use a lime-alkali slip glaze, he failed to reproduce the smooth ...
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Final report on the exhibition. Costs do not of course include the vast amount of time put in by many colleagues at the British Museum
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This exhibition ran from 3 July to 31 December 1997. It included 31 cases, each focusing on a particular case study from the earliest pottery through to the Industrial Revolution. This file contains the text from the explanatory panel... more
This exhibition ran from 3 July to 31 December 1997. It included 31 cases, each focusing on a particular case study from the earliest pottery through to the Industrial Revolution. This file contains the text from the explanatory panel in each of the cases. A book of the same name has chapters on each case study.
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Close Document Image Close Document Printer Image Print This Document! Conservation Information Network (BCIN). Author: Freestone, Ian C.; Rigby, Val Editor: Sayre, Edward V.; Vandiver, Pamela; Druzik, James; Stevenson ...
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A version of this paper was published in Chinese in International Symposium on Ancient Ceramics (ISAC 99), Shanghai (In Chinese) 29-37. The Warring States eyebead comprises a rice ash body overlain by a series of opaque and coloured... more
A version of this paper was published in Chinese in International Symposium on Ancient Ceramics (ISAC 99), Shanghai (In Chinese) 29-37. The Warring States eyebead comprises a rice ash body overlain by a series of opaque and coloured barium-lead-silica glazes. Blue is due to effenbergerite sometimes termed han (or Chinese) Blue. These represent some of the earliest low temperature polychrome glazes in China and are a confluence of glass, pigment and ceramic glaze technology.
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Glazed tiles were employed by the Mughals for the decoration of their monuments in northern India over the sixteenth and seventeenth century. The character and composition of thirty tile samples from Mughal buildings at Delhi, in northern... more
Glazed tiles were employed by the Mughals for the decoration of their monuments in northern India over the sixteenth and seventeenth century. The character and composition of thirty tile samples from Mughal buildings at Delhi, in northern India, were investigated by EPMA-WDS and SEM-EDS. Analysis shows that the tiles have stonepaste bodies, indicating that they form part of the family of Islamic ceramics. The glaze layers are determined to have local characteristics, through comparisons with traditional Indian glass compositions. A local source for the cobalt oxide used to colour dark blue coloured glazes has been suggested. Overall, the study considers the impact of an imported luxury/high status technology on local traditions, and how the two converge to develop a new chaîne operatoire which has aspects of Islamic and indigenous technologies.
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Transparent high lead and tin-opacified lead-alkali glazes have been extensively used throughout Europe and the Near East from their first appearance in the Roman era and the tenth- to eleventh-century Islamic world, respectively, up... more
Transparent high lead and tin-opacified lead-alkali glazes have been extensively used throughout Europe and the Near East from their first appearance in the Roman era and the tenth- to eleventh-century Islamic world, respectively, up until the present day. Using, to a large extent, information which is widely scattered through a diverse range of literature, the methods employed in the production of these two glaze types are first outlined and their merits are then compared with those of alkali glazes in terms of ease of preparation of the glaze mixture, ease of application of the glaze, ease of firing, cost of production, glaze-body fit and visual appearance. The principal advantages of transparent high lead glazes as compared to alkali glazes are shown to be ease of preparation and application of the glaze suspension, low susceptibility to glaze ‘crazing’ and ‘crawling’ and high, optical brilliance. Factors that influence the choice of tin-opacified lead-alkali glazes include ease of production of tin oxide by melting tin and lead metals together; a reduced risk of reduction of lead oxide to lead metal and consequent blackening of the glaze; and, again, low susceptibility to ‘crazing’ and ‘crawling’. Limits of current knowledge regarding these two glaze types and requirements for future research are outlined.
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Firing experiments have been carried out on a clay containing naturally occurring fragments of mollusc shell. The transformation and/or decomposition of mineral phases with temperature was monitored by thermal analysis on the starting... more
Firing experiments have been carried out on a clay containing naturally occurring fragments of mollusc shell. The transformation and/or decomposition of mineral phases with temperature was monitored by thermal analysis on the starting material and compared with X-ray diffraction data on the fired specimens. Scanning electron microscopy revealed systematic changes in the internal microstructure of the shell fragments. Micrometer-sized intra- and inter-layer pores formed in the shells before the complete decomposition of calcite. The shape, dimension and location of the pores within the shell microstructure were found to be directly related to the firing temperature. The analysis of these microstructural features in archaeometric studies offers a good constraint on the estimation of the firing temperature in shell-bearing pottery.
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The microstructures of porcelain and stoneware bodies from north and south China, spanning the period from the Tang to the Ming dynasty (7th–17th centuries ad), were examined in polished sections in a scanning electron microscope (SEM)... more
The microstructures of porcelain and stoneware bodies from north and south China, spanning the period from the Tang to the Ming dynasty (7th–17th centuries ad), were examined in polished sections in a scanning electron microscope (SEM) after etching the sections with hydrofluoric acid (HF). Mullite, present as fine, mainly elongated crystals, is the dominant crystalline phase observed. The bulk chemical compositions of the bodies are determined by energy-dispersive spectrometry in the SEM, and the relative amounts of mullite and quartz present in the different ceramics are estimated from X-ray diffraction measurements. Mullite formed from areas of kaolinitic clay, mica particles and feldspar particles is distinguished through a combination of the arrangement of the mullite crystals, and the associated SiO2/Al2O3 wt% concentration ratios. It is shown that very different microstructures are observed in ceramic bodies produced using kaolinitic clay from north China (Ding porcelain and Jun stoneware), porcelain stone from south China (qingbai and underglaze blue porcelain and Longquan stoneware), and stoneware clays from south China (Yue and Guan stonewares). Therefore, SEM examination of HF-etched, polished sections of the bodies of high-refractory ceramics has considerable potential for investigating the raw materials used in their production.
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The remains of ancient metallurgy are prolific: enormous slag heaps cover the ancient smelting sites. Only rarely are the remains still in situ , more usually the furnace fragments, other refractories and even spillages of the metals are... more
The remains of ancient metallurgy are prolific: enormous slag heaps cover the ancient smelting sites. Only rarely are the remains still in situ , more usually the furnace fragments, other refractories and even spillages of the metals are buried in slag heaps. In fact, their ...
... Author: Tite, Michael S.; Hughes, Michael J.; Freestone, Ian C.; Meeks, Nigel D.; Bimson, Mavis Editor: Rothenberg, Beno Title Article/Chapter: "Technological characterisation of refractory ceramics from... more
... Author: Tite, Michael S.; Hughes, Michael J.; Freestone, Ian C.; Meeks, Nigel D.; Bimson, Mavis Editor: Rothenberg, Beno Title Article/Chapter: "Technological characterisation of refractory ceramics from Timna" Title of Source: The ancient metallurgy of copper: archaeology ...
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Crucibles from the German region of Hesse have been used since the late Middle Ages by alchemists, chemists, assayers, minters and metallurgists 1, 2, 3 , but the factors responsible for their superior quality are unknown and several... more
Crucibles from the German region of Hesse have been used since the late Middle Ages by alchemists, chemists, assayers, minters and metallurgists 1, 2, 3 , but the factors responsible for their superior quality are unknown and several historically documented attempts to replicate their construction have failed 2, 4, 5 . Here we show that the secret behind the remarkable properties of these early crucibles is mullite, an aluminium silicate that is now widely used in modern advanced ceramics. ... Hessian crucibles (Fig. 1a) were established by the fifteenth century and ...
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Post-excavation iron corrosion may be accelerated by the presence of Cl−, leading to conservation methods designed to remove Cl. This study exploits a unique opportunity to assess 35 years of conservation applied to cast-iron cannon shot... more
Post-excavation iron corrosion may be accelerated by the presence of Cl−, leading to conservation methods designed to remove Cl. This study exploits a unique opportunity to assess 35 years of conservation applied to cast-iron cannon shot excavated from the Mary Rose. A combination of synchrotron X-ray powder diffraction (SXPD), absorption spectroscopy (XAS), and fluorescence (XRF) mapping have been used to characterise the impact of conservation on the crystalline corrosion products, chlorine distribution, and speciation. The chlorinated phase akaganeite, β-FeO(OH,Cl), was found on shot washed in corrosion inhibitor Hostacor IT with or without an additional reduction stage. No chlorinated phases were observed on the surface of shot stored in sodium sesquicarbonate (Na2CO3/NaHCO3); however, hibbingite, β-Fe2(OH)3Cl, was present in metal pores. It is proposed that surface β-FeO(OH,Cl) formed in the early stages of active conservation owing to oxidation of β-Fe2(OH)3Cl at near-neutral pH.
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Corrosion products on three bronze swords found in tombs dating from the Warring States period at Lijiaba site, Yun-yang county, Chongqing were characterized by Raman and X-ray fluorescence spectroscopies. The major corrosion products... more
Corrosion products on three bronze swords found in tombs dating from the Warring States period at Lijiaba site, Yun-yang county, Chongqing were characterized by Raman and X-ray fluorescence spectroscopies. The major corrosion products were cuprite, malachite, cerussite and cassiterite, along with the copper and lead phosphates, libethenite
and pyromorphite. The presence of libethenite and pyromorphite which have been reported infrequently in bronze corrosion products were attributed to the pH, humidity and phosphorus released by the decomposition of the adjacent bodies in the burial environment.
and pyromorphite. The presence of libethenite and pyromorphite which have been reported infrequently in bronze corrosion products were attributed to the pH, humidity and phosphorus released by the decomposition of the adjacent bodies in the burial environment.
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Loess bronze moulds from Anyang are examined by SEM-EDS and compared with other ceramic materials
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Copper alloys with controlled contents of Sn, Ag and Au were treated with methods and solutions that mimic those used in ancient and traditional procedures for the production of black bronze. Examination of the resulting patinas with... more
Copper alloys with controlled contents of Sn, Ag and Au were treated with methods and solutions that mimic those used in ancient and traditional procedures for the production of black bronze. Examination of the resulting patinas with colorimetry, SEM–EDS, TEM, Raman spectroscopy and XRD revealed no systematic differences according to the fabrication method, whereas patina homogeneity and colour in those alloys that did not contain precious metal were affected by superficial work. Patina microstructure determines adherence and coverage, and depends upon the solution used irrespective of the alloy composition, but the colour of the patina is mainly related to the alloy composition. Gold promotes the development of cuprite, slowing the oxidation to tenorite in the corrosion process. Gold additions produce a more uniform patina as well as a desirable blue–black tone, which is likely to have been a factor in alloy selection.
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... ABIM - An Annotated Bibliography of Indian Medicine. The production of lead, silver and zinc in early India. -. Author(s): Craddock, PT, IC Freestone, LK Gurjar, AP Middleton and L. Willies. Title: The production of lead, silver and... more
... ABIM - An Annotated Bibliography of Indian Medicine. The production of lead, silver and zinc in early India. -. Author(s): Craddock, PT, IC Freestone, LK Gurjar, AP Middleton and L. Willies. Title: The production of lead, silver and zinc in early India. Publication date: 1989. ...
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Analysis of residual stress in archaeological copper alloy artefacts by neutron diffraction has considerable potential for the investigation of early fabrication processes. However, residual stresses in metals are known to relax due to... more
Analysis of residual stress in archaeological copper alloy artefacts by neutron diffraction has considerable potential for the investigation of early fabrication processes. However, residual stresses in metals are known to relax due to conditions similar to those encountered during burial, corrosion and conservation. In this pilot study, we investigate the effects of corrosion and conservation on a small group of replica copper ingots. Although corrosion and light cleaning do indeed cause some relaxation of stresses in the metal, corrosion having the most significant effect, the basic patterns and major features of the stress profiles may still be seen.
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ABSTRACT
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These images accompany the paper of the same name. They also include several other items which show similar patinas, including the Dancing Lar mentioned in the paper. Also additional SEM and optical micrography of the pyroxene crystal... more
These images accompany the paper of the same name. They also include several other items which show similar patinas, including the Dancing Lar mentioned in the paper. Also additional SEM and optical micrography of the pyroxene crystal removed from the patina.
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... metamorphic environment equivalent to greenschist facies. This suggests that the quartz was obtained from Brazil or Madagascar, areas far outside pre-Columbiantrade networks. Recent archival research revealed that the ...
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The extent of the low temperature field of liquid immiscibility in the system K2O-FeO-Al2O3-SiO2 in the vicinity of the plane fayalite-leucite-silica has been experimentally determined. The combination of direct oxygen buffering with the... more
The extent of the low temperature field of liquid immiscibility in the system K2O-FeO-Al2O3-SiO2 in the vicinity of the plane fayalite-leucite-silica has been experimentally determined. The combination of direct oxygen buffering with the use of a zirconia probe to monitor oxygen activity has allowed minimisation of K2O-loss in the experiments while oxygen activity appropriate to the iron-wüstite buffer has been maintained. The four-phase assemblage, fayalite+tridymite+FeO-rich liquid+SiO2-rich liquid, isobaric univariant in the quaternary system, occurs over a very small temperature range at about 1,163° C on the iron-wüstite buffer. Both liquids appear to be in a coprecipitation relationship with tridymite and fayalite although the relationships between the two liquids are more complicated. The distribution of elements between the two coexisting liquids shows an interesting concordance when plotted in a new way. The results make sense in terms of current knowledge about silicate liquid structure, including the (familiar) observation that K/Al in the SiO2-rich liquid is always greater than in the coexisting FeO-rich liquid.
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The two-liquid field between alkali-carbonate liquids and phonolite or nephelinite magmas from the Oldoinyo Lengai volcano has been determined between 0.7 and 7.6 kb and 900°–1,250° C. The miscibility gap expands with increase in $P_{CO_2... more
The two-liquid field between alkali-carbonate liquids and phonolite or nephelinite magmas from the Oldoinyo Lengai volcano has been determined between 0.7 and 7.6 kb and 900°–1,250° C. The miscibility gap expands with increase in $P_{CO_2 }$ and decrease in temperature. Concomitantly there is a rotation of tie-lines so that the carbonate liquids become richer in CaO. The element distribution between the melts indicates that a carbonate liquid equivalent in composition to Oldoinyo Lengai natrocarbonatite lava would have separated from a phonolitic rather than a nephelinitic magma. CO2-saturated nephelinites coexist with carbonate liquids much richer in CaO than the Lengai carbonatites, but even so these liquids have high alkali concentrations. If the sövites of hypabyssal and plutonic ijolite-carbonatite complexes originated by liquid immiscibility, then large quantities of alkalis have been lost, as is suggested by fenitization and related phenomena. The miscibility gap closes away from Na2O-rich compositions, so that the tendency to exsolve a carbonatite melt is greater in salic than in mafic silicate magmas. The two-liquid field does not approach kimberlitic compositions over the range of pressures studied, suggesting that the globular textures observed in many kimberlite sills and dykes may be the result of processes other than liquid immiscibility at crustal pressures.
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THE existence of carbonatite magmas has been generally accepted1, but their origin remains uncertain. The more favoured petrogenetic models include: (1) direct partial melting of the upper mantle2-5 (2) fractional crystallisation of... more
THE existence of carbonatite magmas has been generally accepted1, but their origin remains uncertain. The more favoured petrogenetic models include: (1) direct partial melting of the upper mantle2-5 (2) fractional crystallisation of CO2-rich alkaline silicate magma6; and (3) separation of an immiscible carbonate melt from an initially homogeneous CO2-rich alkaline silicate magma7-10. Experiments have shown all of these processes to be feasible5-7, and each may generate the geochemical characteristics of carbonatite, such as enrichment in rare earths and other incompatible trace and minor elements11,12, and low 87Sr/86Sr ratios13. Here we discuss the role of immiscibility, and report new experimental data which demonstrate for the first time that liquid immiscibility does occur between silicate and carbonate liquids of the compositions found in nature.
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The classification of materials is a practice with deep roots in the past, but the multifarious properties of glass lent it an intermediary or ambiguous position in many classification systems: from the Bronze Age description of glasses... more
The classification of materials is a practice with deep roots in the past, but the multifarious properties of glass lent it an intermediary or ambiguous position in many classification systems: from the Bronze Age description of glasses with reference to precious stones, and the role of glasses in alchemical theories of the Middle Ages, to the difficulties encountered by modern science in attempting to determine its physical state, glass has resisted classification. This ambiguous position also stems from the chameleonic properties of man-made glasses, which can be worked to shape when either hot or cold, can be produced in almost limitless hues, and can be either transparent or opaque. Glass is particularly suited to mimicking the properties of stones and gemstones, though it also has strong connections with metals and pottery. Much like the plastics of the twentieth century, glass may at times in its history have been a byword for ersatz. Yet imitation was often a very complex matter, for the properties of glass also lend it a unique value in many applications. Just as the Roman vessel known as the Portland Vase originally reflected cameo work in natural stones, which would have been impossible to achieve on such a large object, so it too was imitated in ceramic by Josiah Wedgwood in the late 18th century. The aim of this study day is to explore aspects of the use of glass in imitation of other materials. What purposes were behind this practice, and how was it achieved from a technical perspective? Which materials were mimicked, and how did this affect the value of the glass itself and the material it was imitating? What was the purpose of mimesis and imitation at different times?
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Recent work on glazed, industrial and architectural ceramics from the Bronze Age to the early modern periods
Research Interests: Archaeometry, Ceramics (Art History), Medieval ceramics (Archaeology), Archaeometallurgy, Ceramics (Archaeology), and 3 moreMedieval Islamic Ceramics, Scientific Analysis of Archaeological Ceramics, and Archaeology, Conservation of Archaeological Ceramics, Epoch Castrexa, Restoration of Archaeological Ceramics, Site of San Cibrán of The (Ourense, Spain), Conservation and Restoration Treatment, IInd Iron Age
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In the late 1980s and early 1990s, I worked extensively with Val Rigby, Andrew Middleton and Sylvia Humphrey on the petrography of pottery from Yorkshire and Humberside, particularly types tempered with glacial erratics and crushed... more
In the late 1980s and early 1990s, I worked extensively with Val Rigby, Andrew Middleton and Sylvia Humphrey on the petrography of pottery from Yorkshire and Humberside, particularly types tempered with glacial erratics and crushed calcite. Very few of these data were published, beyond a short report on Burton Fleming by Freestone and Middleton (1991). Additionally, a poster presentation on the implications of the use of crushed erratics in pottery was presented at the 23rd International Symposium on Archaeometry in Naples, April 1983. I am therefore making the reports more widely available before they are completely forgotten.
I should issue a health warning. These reports were subject only to an internal review process, and were not independently refereed. Furthermore, times change and understanding improves. To use the results for research purposes, it is recommended that you look at the thin sections, which are held in the British Museum.
This file contains reports on the petrography of pottery from Burton Fleming, West Heslerton, Wetwang, Scarborough, Weaverthorpe, Cottam, Thornton Dale, Ulrome and Staple Howe.
I should issue a health warning. These reports were subject only to an internal review process, and were not independently refereed. Furthermore, times change and understanding improves. To use the results for research purposes, it is recommended that you look at the thin sections, which are held in the British Museum.
This file contains reports on the petrography of pottery from Burton Fleming, West Heslerton, Wetwang, Scarborough, Weaverthorpe, Cottam, Thornton Dale, Ulrome and Staple Howe.
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This project focuses on the analysis of twenty fragments of stained window glass excavated in a French monastic site and dated between the end of the 8th and the beginning of the 9th century AD. On a large number of pieces some red traces... more
This project focuses on the analysis of twenty fragments of stained window glass excavated in a French monastic site and dated between the end of the 8th and the beginning of the 9th century AD. On a large number of pieces some red traces are visible, very powdery and prone to detach. The main focus of the study was the investigation of the nature and function of these traces, whether they were added intentionally or are the result of post-depositional processes and whether they could be associated with a specific technological tradition. Scanning electron microscopy with energy dispersive X-ray analysis showed that the red traces are an intentional mixture of a red iron-rich pigment and a calcium-rich material. An initial interpretation as a painted decorative layer on the glass has later been ruled out owing to their extremely detachable nature and the fact that they would not transmit light, an essential feature of coloured decoration in windows. Thanks to the testimony of Theophilus, who wrote in the early twelfth century, it has been possible to interpret the traces as the outlines drawn upon the glass to guide the cutting of the pieces according to an underlying design painted on a board beneath the glass. The fact that paint compositions are not standardized supports this interpretation as they only had a functional value and the glassworkers did not need precise recipes and corresponding ratios of chemical elements. Coupled with the use of a potash-lime-silica glass for the windows, and several examples of fused lead-silicate grisaille paint, this assemblage demonstrates the very early development of a window technology which is traditionally associated with the high medieval period.
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Relatively little is known about stained glass windows in England predating c. 1170; however, art-historical evaluation by Caviness (1987) argued that four figures from the “Ancestors series” of Canterbury Cathedral, usually dated to the... more
Relatively little is known about stained glass windows in England predating c. 1170; however, art-historical evaluation by Caviness (1987) argued that four figures from the “Ancestors series” of Canterbury Cathedral, usually dated to the late 12th and early 13th century, in fact date earlier (c. 1130–1160). This would place them amongst the earliest stained glass in England, and the world. Building on our previous work, we address Caviness’s hypothesis using a methodology based upon analysis of a few, well-measured heavy trace elements and a 3D-printed attachment for a pXRF spectrometer that facilitates in situ analysis. The results confirm two major periods of “recycling” or re-using medieval glass. The first is consistent with Caviness’s argument that figures predating the 1174 fire were reused in the early 13th century. The results suggest that in addition to figures, ornamental borders were reused, indicating the presence of more early glass than previously thought. In the secon...
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The surfaces of 30 pieces of glass from panel 3b of the Great East Window of York Minster (1405-1408 CE) were analyzed by handheld portable X-ray fluorescence (pXRF) and small samples from the same pieces were analyzed by electron... more
The surfaces of 30 pieces of glass from panel 3b of the Great East Window of York Minster (1405-1408 CE) were analyzed by handheld portable X-ray fluorescence (pXRF) and small samples from the same pieces were analyzed by electron microprobe (EPMA). Comparison of the two methods reveals significant divergences which are not systematic, particularly for elements lighter than Ti. Rather than a problem with pXRF calibration or correction software, the non-systematic error is attributable to the presence of a thin surface layer of weathered glass. Analysis of the depths of X-ray generation indicate that virtually all X-rays characteristic of Ca and K are generated within the top 50 µm of the glass. However, for heavier elements such as Rb, Sr and Zr, most emitted X-rays are generated below 100 µm. Using pXRF data for the heavier elements, it is possible to replicate the compositional groupings identified by quantitative EPMA. White glass in the window is likely to have originated in Eng...
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Kunicki-Goldfinge JJ, Mester E, Freestone IC. (2013) The chemical composition of glass from the Hungarian glasshouses and glass utilized in Hungary from the 14th century to the 17th century. In: Michalik J, Smułek W, Godlewska-Para E (eds). Annual Report 2012. Warszawa: Institute of Nuclear Chemi...more