120 research outputs found
Mosaic tesserae from San Vincenzo compared to Roman tesserae.
No full text<p>39 mosaic tesserae of different colours from San Vincenzo compared to 95 glass tesserae from first- to third-century mosaics from Italy and North Africa in terms of their lime and alumina concentrations (Roman sample excludes opaque reds; Freestone unpublished data).</p
Compositional identification of 6th c. AD glass from the Lower Danube
No full textA group of finds (vessels, raw glass chunks, window panes) from three sites in present-day Bulgaria was selected as representative of the circulation and usage of glass in the Lower Danube region during the 6th c. AD. In total, 79 samples were analysed by EPMA and/or LA-ICP-MS techniques. The data quality was assessed for each analytical run according to the measurement of reference glasses and to pairs of results obtained from representative samples of archaeological glass analysed by both techniques. Combining EPMA and LA-ICP-MS data allowed a sufficiently consistent and unified set of primary results to be formed. As already suggested in an earlier preliminary paper, only a single glass composition was found to dominate the 6th c. contexts in the region. The current study recognises this 6th c. glass from the Lower Danube as identical with the so called 'Serie 2.1.' defined by D. Foy and co-workers (2003) in various assemblages in Southern France and North Africa. The major, minor and trace oxide evidence presented here indicates that this is a distinct primary glass composition, with an iron-rich sub-group tentatively differentiated within the main group. Accordingly, an attempt is made to situate it relative to the other main primary compositions in the region. The proposed interpretation is that the 6th c. glass should not be linked to the HIMT glass despite the nominal similarity between them due to their elevated iron oxide, manganese, and titania concentrations. Instead, a possible link between the geochemical characteristics of the 6th c. glass and an earlier group of manganese decolourised glass, equivalent to 'Serie 3.2.' outlined by D. Foy and co-workers (2003) is suggested. This may imply the use of sand from a broadly identical geological area, hence it is possible that both the 6th c. glass and the manganese decolourised composition are likely to share a common origin
Technical challenges in the manufacture of opaque turquoise glass in the medieval Islamic world
No full textSome implications of the use of wood ash in Chinese Yue ware glazes of the late Tang dynasty
No full textTheophilus and the Composition of Medieval Glass
No full textABSTRACTCurrent 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.</jats:p
The Provenance of Ancient Glass through Compositional Analysis
No full textABSTRACTRecent developments in the understanding of the low-magnesia soda-lime-silica or “natron” glasses of the first millennium A.D. are reviewed. It appears that glass production was divided between a small number of primary glass making centres, situated mainly in the Near East, and a large number of secondary fabrication workshops that remelted and shaped the lumps of raw, premelted glass. Glass may be related to its primary production group by elemental analysis and, where there are data from workshops, to the production centre or region. The recycling of old glass is revealed by trace element analysis, due to the contamination of primary glass compositions by small quantities of coloured glass incorporated in the recycled material. The analysis of isotopes of Sr and Pb allows the geological environment of the raw materials to be inferred and in some cases, provenance to be predicted.</jats:p
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