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Composition and colouring agents of historical Islamic glazes measured with EPMA and mu -XRD2

Rena Gradmann and Ulrich Schuessler
Composition and colouring agents of historical Islamic glazes measured with EPMA and mu -XRD2 (in Characterization, diagnosis and conservation of cultural heritage, Germana Barone (prefacer) and Pierfranco Lattanzi (prefacer))
European Journal of Mineralogy (June 2015) 27 (3): 325-335

Abstract

Glazes from tiles of representative historic Islamic buildings and tableware ceramic from Central Asia, the Middle East, Asia Minor and North Africa were analysed by electron probe microanalysis (EPMA) and two-dimensional micro-X-ray powder diffraction (mu -XRD (super 2) ). From major element compositions, three main glaze types were identified: alkali, alkali-lead and lead glazes. Quartz frit and clay ceramics form the substrates of the glazes. A slight influence of the ceramic on the glaze compositions can be found for SiO (sub 2) , Al (sub 2) O (sub 3) and K (sub 2) O, but only for quartz frit substrates. PbO and/or alkali oxides were used as fluxes. Na (sub 2) O is the dominant oxide in the alkali flux. MgO and P (sub 2) O (sub 5) are the decisive components for the discrimination between mineral soda and plant ash as a source of the alkali flux. The use of plant ash beside the established mineral soda as flux for the glazes was introduced during the 13 (super th) century in Iran, latest during the 13 (super th) /14 (super th) century in Afghanistan, and during the 14 (super th) /15 (super th) century in Uzbekistan. Hence, a change of the flux happened later for the glazes than for local glass of the same regions. Lead-glaze compositions occur in almost all considered epochs and locations. Colouring ions are Co (super 2+) (blue), Cu (super 2+) (green in a Pb-rich matrix), Fe (super 3+) and Mn (super 4+) (brown/black) and Mn (super 3+) (violet). Pigments, such as SnO (sub 2) , SiO (sub 2) and PbSiO (sub 4) , are whitening agents; Pb (sub 2) Sn (sub 2) O (sub 6) was used for yellow colours. Iron-containing clinopyroxenes and Cu-Cr-Mn-oxides are found in black glazes.


ISSN: 0935-1221
EISSN: 1617-4011
Serial Title: European Journal of Mineralogy
Serial Volume: 27
Serial Issue: 3
Title: Composition and colouring agents of historical Islamic glazes measured with EPMA and mu -XRD2
Title: Characterization, diagnosis and conservation of cultural heritage
Author(s): Gradmann, RenaSchuessler, Ulrich
Author(s): Barone, Germanaprefacer
Author(s): Lattanzi, Pierfrancoprefacer
Affiliation: University Wuerzburg, Department of Geodynamics and Geomaterial Research, Wurzburg, Germany
Affiliation: University of Catania, Catania, Italy
Pages: 325-335
Published: 201506
Text Language: English
Publisher: Schweizerbart'sche Verlagsbuchhandlung (Naegele u. Obermiller), Stuttgart, Germany
Meeting name: International school innovative methodologies for the characterisation, diagnosis and conservation of the cultural heritage
Meeting location: Catania, ITA, Italy
Meeting date: 20140701July 1-4, 2014
References: 39
Accession Number: 2015-087036
Categories: General geochemistryQuaternary geology
Document Type: Serial Conference document
Bibliographic Level: Analytic
Illustration Description: illus. incl. 3 tables, sketch map
N29°00'00" - N38°15'00", E60°00'00" - E75°00'00"
N37°00'00" - N53°00'00", E43°00'00" - E86°00'00"
N25°00'00" - N39°30'00", E44°00'00" - E63°19'60"
N19°00'00" - N37°30'00", W15°30'00" - E36°00'00"
N35°49'60" - N42°00'00", E26°00'00" - E44°45'00"
N37°00'00" - N45°00'00", E55°00'00" - E72°00'00"
Secondary Affiliation: University of Cagliari, ITA, Italy
Country of Publication: Germany
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Abstract, copyright, Schweizerbart'sche Verlagsbuchhandlung. Reference includes data from GeoScienceWorld, Alexandria, VA, United States
Update Code: 201537
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