Roman Glass Research Articles

Quantification of sodium in ancient Roman glasses with ion beam analysis

Concentrations of light elements (Na, Al, Si) in glass have been profiled by comparing the PIGE yields as a function of beam energy to those of a glass standard in combination with PIXE measurements which are used to determine the specific energy loss of protons in the unknown glasses. The technique has been tested on a known sample and applied to a few Roman natron glasses giving results compatible with the morphology of the archaeological samples, as deduced from microscopy. The results have suggested some considerations on the systematic use of the PIGE technique in the determination of bulk sodium concentration in ancient materials.

The development of growth rings on ancient glass surfaces: Description and simulation of the weathering

The present work investigates the weathering process of glass surfaces with the formation of corrosion growth rings investigated by X-ray photoelectron spectroscopy, optical microscope, environmental scanning electron microscope and particle induced X-ray emission. The analysed samples are both ancient and recent glasses. The first set of samples is constituted by Roman glass fragments originally belonging to the load of the Iulia Felix ship, sunken in the Northern Adriatic sea (Grado, Italy) during II century AD. The samples were already investigated in the past [F. Barbana, R. Bertoncello, L. Milanese, C. Sada, J. Non-Cryst. Solids 337 (2) (2004) 136; B. Dal Bianco, R. Bertoncello, L. Milanese, S. Barison, J. Non-Cryst. Solids 343 (2004) 91; B. Dal Bianco, R. Bertoncello, L. Milanese, S. Barison, Surface Eng. 21 (5–6) (2005) 393; B. Dal Bianco, R. Bertoncello, L. Milanese, S. Barison, Archaeometry 47 (2) (2005) 353], but their production process is still unknown. The second set of samples belongs to the stained window of S. Giovanni church in Polegge (Vicenza, Italy) and it is dated to 1930 ca. The glass production process is well known. In fact, every tessera is made of soda-lime glass. On one side only, the glass is coated with a green pigment (low melting temperature glass) and then heated in oven in order to fix it on the glass. The window is then mounted and fixed to the wall. Unfortunately, during this procedure, the window was positioned inside-out, so that the painted surface was exposed to the direct action of the atmospheric conditions. This anomaly favoured the fast degradation of the tessera, with the presence of concentric rings at the surface. Another set of samples was produced in order to simulate the effects of moisture at the glass surface, using an industrial soda-lime glass and coating it with a painting originally used in 1930s. The comparisons between the corrosion of the three sets of samples suggest that the Iulia Felix glasses could have been prepared with the same technique.

Degradation processes in colourless Roman glass: cases from the Bocholtz burial

A group of Roman glass objects from the Bocholtz burial in the SW of Limburg (The Netherlands) was found to have been subject to varying degrees of degradation. Many of the 25 colourless glass objects were fragmented to pieces <0.1 cm (“sugared”), whereas the three transparent blue-green glass objects were in near-pristine state. Analyses using SEM, XRF and EDS revealed that the fragmentation was the direct result of the intense leaching of Na 2O from the glass structure and its replacement with water. The resulting gel layers with low-Na 2O contents and large amounts of water are sensitive to cracking when they dry out. Thin-walled glass appears to be less sensitive to cracking from the resulting stress than thick-walled glass. Local differences in the moisture regime during burial also influence the severity of the glass degradation. Glass with low concentrations of CaO seems to be the most sensitive to this form of degradation. The typical blue-green Roman glass is less sensitive as it generally has considerably higher concentrations of CaO. “Sugared” glass has – until now – only been reported in a small number of high-status burials. However, glass fragments that are degraded as strongly as some of the objects in the Bocholtz burial may have been overlooked in other archaeological settings (e.g. settlements), especially in coarse-grained soils or soils containing debris or rock fragments. As a result, the archaeological record for Roman glass may be biased towards the “typical” blue-green transparent glass objects.

Advantages of scanning-mode ion beam analysis for the study of Cultural Heritage

In this paper, we discuss the convenience of performing external PIXE and PIGE measurements by scanning relatively large areas (some mm2) with a beam size of the order of hundred microns, rather than performing “spot” compositional analysis. Examples of test runs on samples of archaeometric interest are presented: scanning-mode measurements of ancient inks, Roman glass and metal point drawings clearly demonstrate that using this procedure to perform IBA may become fundamental to avoid deceptive information and to obtain more reliable quantitative results.

“Reflections of Roman Glass in Chinese Ceramics”

“Reflections of Roman Glass in Chinese Ceramics”

Redcastle, Lunan Bay, Angus

Cropmarks of a cemetery containing square- and round-ditched burials were excavated at Redcastle in 1997 and 1998. A total of sixteen graves was recorded: five in square barrows, two in round barrows and nine unenclosed graves. Another round barrow is clearly visible on the aerial photograph outside the excavation area. Preservation of the graves and the human remains therein varied considerably. Analysis of the bones identified two females, three possible females and one possible male. Radiocarbon dating showed that the burials dated from the third to eighth centuries AD. There was no readily apparent connection between gender or age and the use of square or round ditches to enclose the graves. Some evidence was recovered for Neolithic activity in the area while the remains of a timber-lined souterrain were also excavated. The fill of the souterrain contained a range of artefacts including native and Roman pottery, Roman glass and iron tools. Detailed palaeoenvironmental studies were undertaken of the basal deposits in an attempt to clarify the use of the souterrain. Radiocarbon dates indicate that it was in use prior to and during the first to fourth centuries AD. Includes separately authored reports on

CT: A New Nondestructive Method for Visualizing and Characterizing Ancient Roman Glass Fragments in Situ in Blocks of Soil

A rare, complete ancient Roman burial site was discovered near the Dutch village of Bocholtz. In addition to many preserved grave offerings, there were countless fragments of deteriorated glass objects still buried in the ground. This glass was in very poor condition, however, and there was no possibility of excavating it directly. Instead, archeologists working at the site decided to dig up blocks of soil containing the glass fragments. High-resolution spiral computed tomography (CT) with multiplanar reformation, shaded-surface-display rendering, and volume rendering was used to obtain detailed information about the position, number, and form of the deteriorated glass fragments. CT-guided removal of the soil made it possible to restore some of the objects excavated from the blocks. In five of the 14 excavated objects, a correct Isings classification could be made based on the CT findings. In addition, CT was very important for the reconstruction of the layout of the burial chamber, the compilation of a list of grave contents, and the positioning of these contents within the chamber.

SAND FOR ROMAN GLASS PRODUCTION: AN EXPERIMENTAL AND PHILOLOGICAL STUDY ON SOURCE OF SUPPLY*

This paper reports the results of an experimental study performed on Campanian littoral sand, together with a careful philological analysis of Pliny's text concerning the production of glass using the above sand in order to verify its suitability. Accurate chemical and mineralogical characterization of sand samples and experimental glasses was carried out, proving the unsuitability of sand for glass production in its original state. Taking into account both the results of the philological analysis of Pliny's text and the mineralogical assemblage of the sand, a new hypothesis regarding Roman glass‐making technology is proposed and tested here. The technology implies the production of ‘quartz‐enriched’ sand by means of selective grindings according to the different degrees of hardness and cleavage of the mineralogical phases. Melting experiments, carried out on treated sand and in the temperature range compatible with Roman technology, yielded a glass with composition similar to those of typical Roman glasses. Therefore, new perspectives on the sources of supply of raw materials, hitherto debated, are opened up.

PIXE–PIGE analysis of late roman glass fragments

A set of Roman glass fragments, excavated at Sevilla and dated in the 5th century A.D., has been analysed by PIXE and PIGE techniques using the external beam set-up of the 3MV tandem Pelletron accelerator of the CNA at the University of Sevilla.Using a simple quantification method, based on the indirect charge calculation on the sample by monitoring the X-ray induced by the proton beam on the exit window, the composition of the glasses has been determined.From the obtained results, the use of soda as flux has been inferred and colouring manufacture procedures have been identified.

THE PROVENANCE AND TECHNOLOGY OF NEAR EASTERN GLASS: OXYGEN ISOTOPES BY LASER FLUORINATION AS A COMPLEMENT TO STRONTIUM*

The ability to make rapid measurements on small samples using laser fluorination enhances the potential of oxygen isotopes in the investigation of early inorganic materials and technologies. δ18O and 87Sr/86Sr values are presented for glass from two primary production sites, four secondary production sites and a consumer site in the Near East, dating from Late Antiquity to the medieval period. δ18O is in general slightly less effective than 87Sr/86Sr in discriminating between sources, as the spread of measured values from a single source is somewhat broader relative to the available range. However, while 87Sr/86Sr is derived predominantly from either the lime‐bearing fraction of the glass‐making sand or the plant ash used as a source of alkali, δ18O derives mainly from the silica. Thus the two measurements can provide complementary information. A comparison of δ18O for late Roman – Islamic glasses made on the coast of Syria–Palestine with those of previously analysed glasses from Roman Europe suggests that the European glasses are relatively enriched in 18O. This appears to contradict the view that most Roman glass was made using Levantine sand and possible interpretations are discussed.

Roman coloured and opaque glass: a chemical and spectroscopic study

This work reports the results of an archaeometrical investigation of opaque Roman glass and is mainly focussed on the role of configuration and oxidation state of copper on the colour and opacity of red and green opaque finds (mosaic tesserae, game counters, and glass artefacts) from Sicily and Pompeii excavations. The glass fragments were characterised by EMPA, SEM-EDS, TEM, and XRPD analyses and the copper local environment was investigated using X-ray absorption spectroscopy. The analyses of high-resolution Cu-K edge XANES and EXAFS spectra suggest that, in red samples, copper is present as monovalent cations coordinated to the oxygen atoms of the glass framework, accompanied by metallic clusters. In green samples all the copper cations are incorporated in the glass matrix.

Analyses of colourless Roman glass from Binchester, County Durham

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

Corrosion of archaeological model glasses after 32 years of burial at Ballidon

ABSTRACTThe groundwater corrosion of three archaeological model glass compositions, a replica Roman glass (B1), a medieval glass (B2) and a 17th century glass (B3), recovered from the Ballidon burial site, were investigated by field emission scanning electron microscopy. Given the equivalent burial conditions for all three glasses, the different corrosion mechanisms of these glasses are dependent principally upon composition, and in particular the dominant alkali and network former content. Composition B1 was found to the most durable glass and showed progressive Na leaching coupled with dissolution of the silicate matrix in the outermost 5μm after 32 years of burial. The B2 and B3 compositions were found to be less durable and corroded via congruent dissolution of the silicate matrix and in situ condensation, resulting in the formation of a discrete 5-15μm thick layer after only 1 year of burial. The formation of a protective Ca-rich surface layer was observed for B2, hindering successive inward growth of the dissolution reaction and favouring localised pitting of the extant layer. The protective surface phenomenon was not observed for B3, and a large increase in layer thickness was observed after nine years of burial.

Surface study of water influence on chemical corrosion of Roman glass

Roman glass surfaces have been studied to understand water effects on glass degradation and ionic mobility. Studied specimens mainly come from the Roman ship Iulia Felix, found on the seabed of Grado lagoon (Italy) and dated to the 2nd century AD. Many different corrosion features have been investigated including white glass, glossy glass and growth rings. A typical multilayered structure found in glass is characterised by the presence of different ions in depth profiles. Layered structure is also underlined by variations in hydration oxygen value and adventitious carbon content. Evidence of ion mobility can be found in the study of growth rings, which have metal rich centres rounded with concentric rings. The centres are characterised by the presence of antimony and titanium in their maximum oxidation state: Sb(V) and Ti(IV). The evolution can be understood according to ‘Liesegang ring’ kinetics. Data of glass surfaces have been collected using many techniques, i.e. X-ray photoelectron spectroscopy (XPS), secondary ion mass spectrometry (SIMS) and environmental scanning electron microscopy (ESEM). Several bulk techniques to characterise the specimens have been used.

Colouring and opacifying agents in Roman glass: a multi-technique analytical approach

Colouring and opacifying agents in Roman glass: a multi-technique analytical approach

THE COMPOSITION AND MANUFACTURE OF EARLY MEDIEVAL COLOURED WINDOW GLASS FROM SION (VALAIS, SWITZERLAND)—A ROMAN GLASS‐MAKING TRADITION OR INNOVATIVE CRAFTSMANSHIP?*

Archaeological excavations between 1984 and 2001 at the early Christian cemetery church in Sion, Sous‐le‐Scex (Rhône Valley, Switzerland), brought to light more than 400 pieces of coloured window glass dating from the fifth or sixth centuries ad. The aims of this paper are threefold: first, to characterize the shape, colour and chemical composition of the glass; secondly, to understand whether the production of the coloured window panes followed traditional Roman glazing techniques or was of a more innovative nature; and, thirdly, to provide some indications as to the overall design of these early ornamental glass windows. Forty samples of coloured glass have been analysed by wavelength‐dispersive X‐ray fluorescence. The results of the chemical and the technological studies showed that most of the glass was produced using recycled glass, particularly as a colouring agent. Some of the glass was made of essentially unmodified glass of the Levantine I type. The results taken together seem to confirm that raw glass from this region was widely traded and used between the fourth and seventh centuries ad. The artisans at Sion were apparently still making use of the highly developed techniques of Roman glass production. The colour spectrum, manufacture and design of the windows, however, suggest that they represent early examples of ornamental coloured glass windows.

Stormandsgården ved Lisbjerg kirke –Nye undersøgelser

Stormandsgården ved Lisbjerg kirke –Nye undersøgelser

Glasses on the seabed: surface study of chemical corrosion in sunken Roman glasses

The current work aims to describe surface weathering of ancient glasses in marine environment. All data are collected using different techniques: optical microscopy, RGA, surface techniques (XPS, SEM and SIMS). Three types of glass weathering have been observed: white glass, glossy glass and glass showing growth rings. A compact structure characterizes white glasses, while a porous structure with flaked layers is typical of glossy glasses. White glasses show different abundance of characteristic elements or molecules (Mg(II), Sb(V), Ti(IV) and micro-crystalline silica). Glossy glasses, instead, are characterized by peeling layers of nearly pure silica glass, with small differences in composition owing to ionic mobility phenomena. Data suggest a time relation between white and glossy glasses. Visible growth rings characterize the third class of glass. They are made of titanium and antimony compounds centers surrounded by many rings with the same composition. Their temporal evolution has been explained according to the theory of ‘Liesegang rings’. Hypotheses on antimony and titanium origins are reported.

Alteration and corrosion phenomena in Roman submerged glass fragments

In the present paper the surface analytical techniques of XPS (X-ray photoelectron spectroscopy) and SIMS (secondary ions mass spectrometry) have allowed an understanding of the alteration and corrosion phenomena occurring in Roman glass fragments. The samples come from the seawater archaeological site of the Roman ship Iulia Felix, which sank near Grado (Gorizia, Italy) in the second century A.D. Through XPS the surface concentration of the main chemical elements and their depth profiles have been obtained. Attention has been focused on the oxidation states of the elements, oxygen/silicon ratio, peculiar presence of carbonate salts and concentration trends of some elements in the outer atomic layers. Depth trends of aluminium, calcium, magnesium and carbon were studied also through SIMS depth profiles. The whole set of XPS and SIMS data allows the segregation of particular chemical species and the evolution of the original glass to a multilayer system.

EPMA and µ‐SRXRF analysis and TEM‐based microstructure characterization of a set of Roman glass fragments

AbstractA set of Roman glass fragments, excavated at Bliesbruck–Reinheim (French–German border), were analysed by electron probe microanalysis (EPMA) and micro‐synchrotron radiation‐induced x‐ray fluorescence (µ‐SRXRF) in order to determine the major, minor and trace chemical composition. Based on this analysis, five classes of mono‐coloured glass could be discerned. However, one piece of this set was not mono‐coloured, but consisted of a mixture of brown and white opaque glass. This fragment was investigated using EPMA and transmission electron microscopy (TEM) in order to gain a better insight into its microstructure. Both colours proved to contain small crystalline inhomogeneities. Structural information reveals the form in which the detected elements are present and helps to explain the appearance (e.g. colour) of the material. Copyright © 2004 John Wiley &amp; Sons, Ltd.