Calle Horno del Vidrio—Preliminary Study of Glass Production Remains Found in Granada, Spain, Dated to the 16th and 17th Centuries (original) (raw)
Related papers
2014
A total 103 fragments of Roman glass tableware are studied, unearthed at 7 archaeological sites in the Northwest of the Iberian Peninsula, to establish both similarities and differences in their chemical composition. ICP Mass Spectrometry is used to characterize the chemical composition of: (i) major elements, so as to determine the type of glass; (ii) minor elements, added to improve the properties of the glass; and, (iii) trace elements, as indicators of the base raw material of the glass. Multivariate statistical studies are also used to establish links and significant differences between glass samples, shedding further light on knowledge of Roman glass manufacturing techniques in the Northwest of the Iberian Peninsula. Three main conclusions were achieved. (i) There are significant chemical differences between samples from Braga (Bracara Augusta, Portugal) and the other samples. (ii) These other samples may be sorted into three major groups according to their chemical constituents. (iii) Finally, the statistical analysis and the chemical composition of several glass fragments suggest they were found at some distance from their place of manufacture, requiring the reclassification of their archaeological site of prove-nance.
One hundred and forty-one glass fragments from medieval Ciudad de Vascos (Toledo, Spain) were analysed by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The glasses fall into three types according to the fluxing agents used: mineral natron, soda-rich plant ash, and a combination of soda ash and lead. The natron glasses can be assigned to various established primary production groups of eastern Mediterranean provenance. Different types of plant ash glasses indicate differences in the silica source as well as the plant ash component, reflecting changing supply mechanisms. While the earlier plant ash groups can be related to Islamic glasses from the Near East, both in terms of typol-ogy and composition, the chemical signature of the later samples appear to be specific to glass from the Iberian Peninsula. This has important implications for our understanding of the emerging glass industry in Spain and the distribution patterns of glass groups and raw materials. The plant ash that was used for the Vascos glasses is rich in soda with low levels of potash, similar to ash produced in the eastern Mediterranean. It could therefore be possible that Levantine plant ash was imported and used in Islamic period glass workshops in Spain. Unlike central and northern Europe where an independent glass industry based on potassium-rich wood ash developed during the Carolingian period, the prevalence of soda ash and soda ash lead glass on the Iberian Peninsula indicates its commercial and technological interconnection with the Islamic east. Our study thus traces several stages leading to the development of a specifically Spanish primary glassmaking industry.
First archaeometric study on medieval glass found in Beja (Southern Portugal)
Journal of Medieval Iberian Studies, 2016
During an archaeological intervention that took place in Beja (southern Portugal), at Avenida Miguel Fernandes, between August 2003 and March 2004, a set of 137 silos was discovered. The excavation yielded an assemblage of glass that can be dated between the fourteenth and the seventeenth centuries. For this investigation only the fragments from the medieval contexts were considered in order to provide an overview of the use of glass vessels in a Portuguese town in the fourteenth and fifteenth centuries. A group of eleven medieval glass fragments was chemically characterised by means of µ-PIXE (particle-induced Xray emission) and UV-vis reflectance spectroscopy. Analysis by µ-PIXE enabled the determination of the chemical composition, and UV-vis reflectance spectroscopy was used as a complementary technique to identify the metallic elements responsible for different colours observed in the glasses. Results showed that the analysed objects are in the majority made of a soda-lime silica glass, indicating a connection with the Mediterranean tradition. Cobalt and copper were the colorants used to obtain the blue and turquoise glasses, respectively, whereas iron is responsible for the green and yellow colours.
During an archaeological intervention that took place in Beja (southern Portugal), at Avenida Miguel Fernandes, between August 2003 and March 2004, a set of 137 silos was discovered. The excavation yielded an assemblage of glass that can be dated between the fourteenth and the seventeenth centuries. For this investigation only the fragments from the medieval contexts were considered in order to provide an overview of the use of glass vessels in a Portuguese town in the fourteenth and fifteenth centuries. A group of eleven medieval glass fragments was chemically characterised by means of µ-PIXE (particle-induced Xray emission) and UV-vis reflectance spectroscopy. Analysis by µ-PIXE enabled the determination of the chemical composition, and UV-vis reflectance spectroscopy was used as a complementary technique to identify the metallic elements responsible for different colours observed in the glasses. Results showed that the analysed objects are in the majority made of a soda-lime silica glass, indicating a connection with the Mediterranean tradition. Cobalt and copper were the colorants used to obtain the blue and turquoise glasses, respectively, whereas iron is responsible for the green and yellow colours.
Provenance studies of 18th century potassium-rich archaeological glass from Portugal
Journal of Archaeological Science: Reports, 2017
The archaeometric study of a group of colourless glass fragments recovered from two archaeological excavations performed in Lisbon, Portugal is here reported. The archaeological interventions were performed at Rua do Arsenal (LRA), where the ruins of the Côrte-Real Palace were partially discovered, and at the Roman Theatre Museum (LTR), where the remains of a middle-class house dated to the 18th century were found. The recovered glass fragments are dated between the end of the 17th century and the 18th century, and were chemically characterised with the aim of discussing its provenance. Micro particle induced X-ray emission (μ-PIXE) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) were the chosen analytical methods to characterise the glass composition. All twenty-five fragments proved to be of a potassium-rich composition, where the choice of raw materials seems to have been made with extreme care. This is reflected in general by a composition with low levels of impurities, such as alumina and iron oxide, and high levels of silica. Two compositional groups were identified, that besides differing in other components have different contents of arsenic oxide. None of the groups could be undoubtedly compared with the few known potassium-rich compositions from coeval glass production centres in Europe. The majority of the analysed samples could only be compared, in terms of major oxides, with the potassium-rich production from the Coina Glass Factory in Portugal.
Rare Alkali Elements as Markers of Local Glass Working in Medieval Tolmo de Minateda (Spain)
ChemPlusChem, 2022
Analytical data of Roman and early Islamic glass established several primary glass production groups linked to glassmaking centres in the Levant and in Egypt. In contrast, the activities of secondary glass workshops are largely invisible in the compositional fingerprint of first millennium glass. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) of 261 glass finds from the Visigothic settlement of Tolmo de Minateda (Spain) revealed a site-specific contamination pattern due to secondary glass processing and recycling, namely the enrichment of the glass batch by a unique combination of rare alkali elements (Li, K, Rb, Cs). With a median of 21 ppm, Li is particularly distinctive. Elevated lithium contents (Li > 30 ppm) are also one of the characteristic features of Iberian plant ash glass from the Islamic period. The earliest known examples of this type of glass were found among the ninth-century remains from Tolmo.
Integrated Approaches to the Study of Historical Glass, 2012
LA-ICP-MS is a well acquainted technique for the quantification of a wide range of minor and trace elements present in the glass matrix. The benefit to understand the changes in technological processes or the added value in assessing the provenance and chronology of the raw glass material is however rarely discussed. By selecting a set of 197 Roman black glass artifacts dating between the 1 st and 5 th century AD we aimed to contribute to this issue. The obtained data on the production of glass artifacts helps better understand the constantly evolving patterns in glass consumption throughout the Roman imperial period.
New insights into 17th and 18th century glass from Portugal: study and preservation
2016
Early Modern glass from the Iberian Peninsula has-so far-seldom been investigated. The project, combining chemical analysis with a stylistic approach, and focusing on composition and technology, aims to characterise glass objects circulating in the national territory, in an attempt to identify their origins and to eventually bring to light a Portuguese centre of glass production. The chemical composition of more than 200 glass fragments was determined by means of µ-PIXE down to a level of tens of µg/g. The results obtained allowed one to select some objects to further extend the analysis to the trace and rare earth elements (REE) down to the ng/g level, through the use of LA-ICP-MS. Glass colours and natural hues were studied by means of UV-Vis reflectance spectroscopy and, when necessary, enamels were studied by means of µ-EDXRF and µ-Raman microscopy. From all the objects analysed, it was possible to conclude that the great majority of the glass dating upto the 17 th century, is of a soda-lime-silica type, which indicates a Mediterranean tradition. Venetian or façon-de-Venise shapes were identified, and for some of them a Venetian provenance was confirmed. For other façon-de-Venise shapes, the composition presented differences that led to the conclusion that new façon-de-Venise production centres could be recognised. From the only assemblage containing glass fragments dated to the medieval period, it was possible to attest the presence of Venetian glass in the Portuguese territory from at least the 14 th century. Additional objects showed particular compositional features, such as high and very high alumina contents for instance, that, as far as it is known, do not match up with any of the known glass production centres in Europe. Allying the stylistic characteristics with the glass chemical composition, allowed one to identify some objects possibly belonging to a Portuguese production. Several glass fragments belonging to wine bottles were retrieved from archaeological excavations in Lisbon and were chemically characterised. The chemical analysis revealed an HLLA composition for all of them. For some of these fragments it was possible to propose an English provenance. Besides the chemical characterisation, a systematic analysis of the bottle shape was proposed since the shape can be an important factor in determining its chronology. A small percentage of the fragments were identified chemically as having mixed-alkali compositions, potassium-rich glass, and lead glass compositions. The latter two chemical formulations were found among the assemblages from Lisbon and the objects with these compositions were dated to the 18 th viii century. These constitute evidence that Portugal followed European tendencies in their glass and its compositions. This is the first systematic chemical characterisation of Early Modern glass circulating in Portugal, providing new insights into trade between Portugal and its trade allies. As a part of the study, and to prolong the survival of these glass assemblages, simple and low cost optical sensors were developed for the in situ detection of the organic pollutant formic acid, which is emitted by materials usually used in storage and in the display of glass. The detection of the presence of this acid can play an important role in the preservation of this valuable heritage; glass.
Characterization of 18th century Portuguese glass from Real Fábrica de Vidros de Coina
Journal of Archaeological Science: Reports
A JEOL 6300 Scanning Electron Microscope equipped with an energy dispersive X-ray detector was used This work reports the first systematic chemical characterization of Portuguese 18th century glassware. 28 selected glass fragments, recovered from an archaeological excavation carried out in the site where King D. João V of Portugal established an important glass manufacture, Real Fábrica de Vidros de Coina (Coina Royal Glass Factory), were studied. This factory operated from 1719 until 1747, the year in which the factory was transferred to Marinha Grande. The fragments were analysed by microenergy dispersive X-ray fluorescence (micro-EDXRF), using a portable spectrometer ArtTAX, and scanning electron microscopy (SEM-EDX). The analytical data showed that a large variety of glass types was manufactured in that factory, namely soda-lime glass, mixed-alkali glass, high lime-low alkali glass, potash glass and lead glass. In general, the composition of the glass varies according to the function of the objects. It was demonstrated that micro-EDXRF can be an important tool to characterize museum glass objects when only in situ non-invasive analytical methods are allowed.