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Composition and colouring agents of historical Islamic glazes measured with EPMA and μ-XRD<SUP>2</SUP

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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 (μ-XRD2). 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 SiO2, Al2O3 and K2O, but only for quartz frit substrates. PbO and/or alkali oxides were used as fluxes. Na2O is the dominant oxide in the alkali flux. MgO and P2O5 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 13th century in Iran, latest during the 13th/14th century in Afghanistan, and during the 14th/15th 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 Co2+ (blue), Cu2+ (green in a Pb-rich matrix), Fe3+ and Mn4+ (brown/black) and Mn3+ (violet). Pigments, such as SnO2, SiO2 and PbSiO4, are whitening agents; Pb2Sn2O6 was used for yellow colours. Iron-containing clinopyroxenes and Cu-Cr-Mn-oxides are found in black glazes.

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... The need for having valid and useful heritage documentation is therefore evident and should constitute a priority action in any type of restoration (Almagro, 2013). Unfortunately, in these studied monuments, the availability of proper documentation is very limited (Gradmann et al., 2015;El Halim et al., 2018), as is the case in most historical monuments of emerging or developing countries in the South and East Mediterranean areas. To this end, the aim of this study is to characterize the chemical composition of the different glazes ceramics and to emphasize their evolution over time. ...
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During the 1980s, the late Alexander Kaczmarczyk undertook the analysis of some 1200 glazed Islamic ceramics from Egypt, Iran, Iraq and Syria spanning the period from the eighth to the 14th centuries ad, using a combination of XRF for the glazes, and AAS or PIXE for the bodies. The aim of the present paper is, first, to bring to the attention of researchers into Islamic ceramics the fact that these analytical data are available on the Research Laboratory for Archaeology and the History of Art website, and also that some 400 of the analysed sherds are held in the Research Laboratory. Second, the paper provides a preliminary interpretation of the analytical data in terms of the choice of glaze type (i.e., alkali–lime, lead–alkali and high-lead), tin-opacification, body type (i.e., quartz or stonepaste, calcareous clay, and non-calcareous clay), and colorants.
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A set of laboratory experiments has been developed to determine the nature and importance of the interaction between clay bodies and lead glazes during firing following different thermal paths (firing time and temperature, cooling rates) and using different glaze compositions and different bodies (illitic, kaolinitic, and calcareous clays). It is shown that the interaction consists of a digestion/diffusion process. This process involves (i) decomposition of the phases forming the clay body (digestion), (ii) chemical diffusion of elements between clay body and glaze, and (iii) formation of a layer (interface between clay and glaze) of small K-Pb feldspar crystallites.
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This paper presents a study of a representative selection of lustre ceramics dating from the last quarter of the 10th century AD to the second half of the 13th century AD from Egypt, Syria and Iran. The study concentrates on the structure and chemistry of the lustre itself over the historical period considered and has found a number of significant similarities between the production centres studied. Previous work on the reproduction of lustre under laboratory-controlled conditions allows the archaeological data to be related to the historical technological aspects of lustre production. The results obtained, although restricted to the limited number of samples studied, have demonstrated the occurrence of significant differences and similarities between lustre productions during this period. The possible reasons for these changes are discussed.
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The present work describes an analytical study performed on several pieces of Iranian Ilkhanate glazed ceramics from the Takht-e Soleyman palace (Iran, thirteenth century). Several advanced instrumental techniques, including pyrolysis–gas chromatography–mass spectrometry, Fourier transform IR spectroscopy, light microscopy, X-ray diffraction, scanning electron microscopy–X-ray microanalysis and voltammetry of microparticles, were used. The results obtained led to identification of the chemical and mineralogical composition of the pastes and glazes and the colouring agents. Corrosion processes associated with the extreme burial conditions in which the pieces remained for centuries were characterized in some areas of the glazes. A drying oil was identified as the main component of the organic material that was used as the adhesive for the decorative gold sheets applied on the glazes. This finding is in good agreement with traditional recipes. Interestingly, this drying oil exhibits an unusual composition as the gold sheet preserved it from external ageing agents (light, atmosphere, etc.). Figure Tiles with cobalt blue glaze from the indoor decoration of the Takht-e Soleyman Palace (13th-15th centuries, Iran). a: 20986-8, b: 20986-10 and c:21300a
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The low-temperature dynamics of ultraviscous liquids hold the key to understanding the nature of glass transition and relaxation phenomena, including the potential existence of an ideal thermodynamic glass transition. Unfortunately, existing viscosity models, such as the Vogel-Fulcher-Tammann (VFT) and Avramov-Milchev (AM) equations, exhibit systematic error when extrapolating to low temperatures. We present a model offering an improved description of the viscosity-temperature relationship for both inorganic and organic liquids using the same number of parameters as VFT and AM. The model has a clear physical foundation based on the temperature dependence of configurational entropy, and it offers an accurate prediction of low-temperature isokoms without any singularity at finite temperature. Our results cast doubt on the existence of a Kauzmann entropy catastrophe and associated ideal glass transition.
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Book description: The Pigment Compendium Dictionary is a comprehensive information source for scientists, art historians, conservators and forensic specialists. Drawn together from extensive analystical research into the physical and chemical properties of pigments, this essential reference to pigment names and synonyms describes the inter-relationship of different names and terms. The Dictionary covers the field worldwide from pre-history to the present day, from rock art to interior decoration, from ethnography to contemporary art. Drawing on hundreds of hard-to-obtain documentary sources as well as modern scientific data each term is discussed in detail, giving both its context and composition.
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Seventeenth century polychrome overglaze haft rang tiles found in various regions of Iran (Isfahan, Qazvin, Mashhad, and Mazandaran) were investigated with ultraviolet–visible spectroscopy (UV–Vis), portable X-ray fluorescence (pXRF), energy dispersive X-ray spectroscopy (EDS), and micro-Raman spectroscopy. Two types of glazes were identified, namely low lead-alkali and high lead glazes, in which cobalt, copper, iron, and manganese were used as colourants. Tin oxide and lead-tin yellow were recognised as white and yellow opacifiers respectively. The black line, which was used for delineating the tiles' design, was mainly composed of manganese, iron, and aluminium oxides. The high maturing temperature of this line prevented the low-temperature coloured glazes run together during the firing. Finally, technological differences between haft rang and cuerda seca techniques are highlighted and minai overglazes are briefly compared with haft rang overglazes.
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A group of late 15th - early 16th century Hispano-Moresque glazed tiles from the Monastery of Santa Clara-a-Velha, in Coimbra, were, for the first time, characterised chemically and morphologically. Since the prevailing idea among art historians in Portugal is to judge the Hispano-Moresque tile heritage as Spanish production, the findings concerning technological processes were compared with the Islamic technology in the Iberian Peninsula and latter Hispano-Moresque in Spain. This study is the first analytical indicator of a production technology with some differences from the Hispano-Moresque workshops (such as Seville, Toledo, etc.) and points out to a possible local production. Five different coloured glazes were identified: white, blue, green, amber and black, all displaying high-lead content, as expected for this type of ceramics. Tin oxide was identified in high contents (7e14 wt.%) in white and blue glazes, its crystals homogenously distributed in also very homogeneous glazes, showing similarities with an Islamic glazing technology. On the other hand, Ca-rich thick glazeeceramic interfaces were observed, with many mineral inclusions (wollastonite (CaSiO 3) and also K-feldspars (general formula KAlSi 3 O 8), showing a higher resemblance with a later Hispano-Moresque technology. Other compounds were also identified from reactions involving the colour compound: malayaite (CaSnOSiO 4), bustamite (CaMnSi 2 O 6), braunite ((Mn 2þ , Mn 3þ) 6 O 8 SiO 4), andradite (Ca 3 Fe 2 Si 3 O 12), magnesioferrite (MgFe 2 O 4) and a nickel ferrite (NiFe 2 O 4). The chemical composition of this glazeeceramic interface suggests firing temperatures between 950 C and 1000 C and its thickness implies a single-fire process. The chemical characterisation does not suggest different recipes or different firing processes for cuerda seca and arista tiles.
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Glazed ceramics have been traditionally used in Iran for decorating mosques and some civil historical buildings. In particular, Moarraque glazes have been extensively used in the indoor and outdoor decoration of mosques in Iran since the middle 14th century. The pieces have a complex elaboration based on a main glazed piece corresponding to the skeleton structure of the Shah Abbasi flower, which contains a number of holes, where are placed, mosaic-like, smaller glazed pieces forming a compact and single tile. The present work describes the analytical study performed on the glazes of several pieces of Moarraque tiles from the Ali Ebn Abi Taleb Mosque (Esfahan, Iran), which date back from the 1960s. Several advanced instrumental techniques including light microscopy, scanning electron microscopy–X-ray microanalysis and voltammetry of microparticles, have been used to perform the characterization of the glazes. Results obtained suggest that the analysed pieces were made combining the traditional methodologies used by local craftsmen since the 14th century and modern techniques.
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Microscopic examination and electron microprobe analysis were employed to determine the materials and techniques used to decorate ten glazed types of medieval Islamic ceramics from North Yemen. Eight types were underglaze-painted, one was slip-painted, and one was monochrome glazed. The glazes were of two compositions, soda–silica and lead oxide – silica with annealing temperatures of approximately 835 and 640 °C, respectively. The colourants used in the glazes and paints were cobalt (blue), iron (green), copper (green and blue), and antimony (yellow). Where clay slips or slip-paints were present, alumina enrichment of the glaze had occurred during application or firing, and pigment-paints on top of slip grounds masked enrichment. The Mellor ratio for the lead glazes ranges from 0.68 to 0.74 and is well above the acceptable safety limit of 0.5.
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Coloured tiles from two northern Indian monuments were analysed for their body and glaze composition. The results suggest that three different groups of tiles were used, all comprising a stonepaste body with alkali glaze. One group has strong similarities to a major Indian glass group, known as high alumina mineral natron glass, while the other two are similar to Western and Central Asian plant ash glazes, although with much lower lime content. The colorants conform with those usually employed in pre-modern glazes, with lead-tin yellow Type I and Type II for opaque yellow, copper blue-turquoise, cobalt blue, manganese purple, and green through mixing of lead-tin yellow and copper blue.
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An approach is developed for understanding formation of gel films on glass surfaces during water exposure. Compositional and microstructural data from ir reflection spectroscopy, scanning electron microscopy, and electron microprobe analysis are used with parameters defined from solution-analysis data to produce an SiO2 composition profile of the corroded surface. This model profile is compared with a measured profile and used to interpret differences in corrosion resistance of binary Li2O- and Na2O-SiO2 glasses. Effects of corrosion temperature on surface gel structure are also discussed.
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Iznik tiles dated from the 16th century, copies of tiles and pottery of Théodore Deck from the 19th century and also tiles without any information on their origin were analyzed with both laboratory and portable Raman instruments. As the original tiles are generally fixed on the walls of historical buildings, the portable Raman spectrometer is more convenient for the analysis but the information obtained from the spectra is not very useful because of the medium resolution and complex baseline of the instrument in spite of its speed and ease of use. The Raman signature of the glazes is the most pertinent and easily accessible fingerprint of the artifacts. The differentiation between Iznik ceramics and other samples could be made with Raman spectrometers, according to the specific signature of SiO stretching and bending bands of Iznik glazes. Copyright © 2009 John Wiley & Sons, Ltd.
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The fifteen causes of color derived from a variety of physical and chemical mechanisms are summarized in five Croups in this article. Vibrations and simple excitations explain the colors of incandescence (e.g., flames), gas excitations (neon tube, aurora), and vibrations and rotations (blue ice and water). Ligand-field-effect colors are seen in transition-metal compounds (turquoise, chrome-oxide green) and impurities (ruby, emerald). Molecular orbitals explain the colors of organic compounds (indigo, chlorophyll) and charge-transfer compounds (blue sapphire, lapis lazuli). Energy bands are involved in the colors of metals and alloys (gold, brass), of semiconductors (cadmium yellow, vermillion), doped semiconductors (blue and yellow diamond), and color centers (amethyst, topaz). Geometrical and physical optics are involved in the colors derived from dispersive refraction (rainbow, green flash), scattering(blue sky, blue eyes, red sunset), interference (soap bubbles, iridescent beetles), and diffraction (the corona aureole, opal).
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The advantages using specially designed X-ray-polycapillary microlenses with spot sizes of 50 μm to 200 μm in a commercially available BRUKER D8 DISCOVER GADDS XRD2-microdiffractometer with a standard sealed X-ray tube instead of a microfocus source are shown and compared to commercially available pin hole collimators or monocapillary optics. The application of a focusing X-ray microlens instead of a monocapillary optic with similar spot size leads to an increase of the primary beam flux by a factor of approximately 10 to larger than 100 depending on the additional pinhole used at the exit of the microlens. This additional pinhole can be used to optimize the beam geometry for a better peak profile without additional changes on the setup. Therefore the use of a focusing X-ray microlens instead of a mono capillary optic reduces the measurement time by at least a factor of 10. A factor up to 200 is possible by simple changing the diameter of the exit pinhole – for the price of a wider peak profile. Due to the similar housing the focusing X-ray microlens fits in the standard collimator support enabling switching between collimators, mono-capillaries and the microlens without realignment. This is why no time consuming modification of the microdiffractometer is needed.
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Natron deposits, the best known of which being those at Wadi Natrun in Egypt, have been used as the flux in the production of vitreous materials from the early 4th millennium BC onwards. In the present paper, the history of the use of natron as a flux is traced from its beginnings in the glaze of Badarian steatite beads, through its use in glass production starting in the 1st millennium BC, until its apparent shortage during the 7th to 9th centuries AD, and its subsequent replacement by plant ash during the 9th century AD. Documentary evidence for possible natron sources in Egypt, including the Wadi Natrun, and around the eastern Mediterranean is summarised, and the results of recent fieldwork at the Wadi Natrun and at al-Barnuj in the Western Nile Delta are presented. The possible reasons for the apparent shortage of natron from 7th to 9th centuries AD and its subsequent replacement by plant ash as the flux used in glass production during the 9th century AD are then considered. These include the possibility that, because of the massive scale of glass production, the demand for natron exceeded its supply; the possible effect of climatic changes; and the potentially disruptive role of political events in the Wadi Natrun–Delta region.
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A collection of Islamic glazed pottery shards that were excavated from the archaeological site of Dohaleh/Northern Jordan were chemically analysed. The glazes belong to three different decorative styles. The chemical analysis of the glazes was carried out using energy dispersive x-ray fluorescence. The chemical analysis results enable the classification of the glazes into the three distinct compositional groups with reference to their principal modifier, these are: the alkaline glazes, the high lead glazes and the lead–alkali glazes. In some cases the body fabric was analysed by a combination of petrographic and chemical analysis techniques. The study show that inherited traditional techniques were combined with innovative Islamic techniques were used for the production of the glazes.
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Some plants can hyperaccumulate metal ions that are toxic to virtually all other organisms at low dosages. This trait could be used to clean up metal-contaminated soils. Moreover, the accumulation of heavy metals by plants determines both the micronutrient content and the toxic metal content of our food. Complex interactions of transport and chelating activities control the rates of metal uptake and storage. In recent years, several key steps have been identified at the molecular level, enabling us to initiate transgenic approaches to engineer the transition metal content of plants.
Colour generation and control in glass
  • C R Bamford
Bamford, C.R. (1977): Colour generation and control in glass. Elsevier, New York, 224 p.
the tables. The Corning Museum of Glass
  • R H Brill
Brill, R.H. (1999): Chemical analyses of early glasses, vol. 2 the tables. The Corning Museum of Glass, New York, 553 p.
  • S Gulzar
  • M Wörle
  • J.-P Burg
  • M N Chaudhry
  • E Joseph
  • E Reusser
Gulzar, S., Wörle, M., Burg, J.-P., Chaudhry, M.N., Joseph, E., Reusser, E. (2013): Characterization of 17 th Century Mughal tile glazes from Shahdara Complex, Lahore-Pakistan. J. Cult. Herit., 14, 174-179.
The Potter's dictionary of materials and techniques
  • F Hamer
  • J Hamer
Hamer, F. & Hamer, J. (2004): The Potter's dictionary of materials and techniques. University of Pennsylvania Press, Philadelphia, 422 p.
Lead-glazed slipware of 10 th -11 th century Akhsiket
-,-,-,-, (2007): Lead-glazed slipware of 10 th -11 th century Akhsiket, Uzbekistan. BAR Int. Ser., 8, 145-148.
Chemical and mineralogical characterization of Sasanian and early Islamic glazed ceramics from the Deh Luran plain, southwestern Iran. Archaeometry
  • D V Hill
  • R J Speakman
  • M D Glascok
Hill, D.V., Speakman, R.J., Glascok, M.D. (2004): Chemical and mineralogical characterization of Sasanian and early Islamic glazed ceramics from the Deh Luran plain, southwestern Iran. Archaeometry, 46, 585-605.
Keramische Glasuren: Grundlagen
  • W E Matthes
Matthes, W.E. (1990): Keramische Glasuren: Grundlagen, Eigenschaften, Rezepte, Anwendung. Augustus-Verlag, Augsburg, 501 p.
Giallorino: Storia dei Pigmenti gialli di Natura Sintetica. De Luca Editori
  • C Seccaroni
Seccaroni, C. (2006): Giallorino: Storia dei Pigmenti gialli di Natura Sintetica. De Luca Editori d'Arte, Rome, 399 p.