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Characterisation of inorganic pigments in ancient glass beads by means of Raman microspectroscopy, microprobe analysis and X‐ray diffractometry

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Abstract

Ancient coloured glass beads from Sri Lanka and Oman were analysed by Raman microspectroscopy for non-destructive identification of inorganic pigments in the glass. Calcium phosphate (Ca3(PO4)2), cassiterite (SnO2), cuprite (Cu2O) and a Pb(Sn,Si)O3-type lead tin oxide were found to be used as colouring agents. Moreover, a distinction between lead-based and alkali-based glass matrices could be made. Electron microprobe analysis and X-ray diffractometry were performed to show the capability of Raman microspectroscopy in comparison to these methods for answering archaeometric questions. Copyright © 2006 John Wiley & Sons, Ltd.

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... The proposed approach to the compositional question is nondestructive and multi-technique, as commonly chosen for the study of glassy materials. [19][20][21] The combination of molecular techniques, such as Raman spectroscopy, with one or more other mainly elemental techniques [22][23][24] is well-known for the study of glass archaeological artifacts, and is especially favored as it allows for the characterization of such materials in a nondestructive way. 25 Moreover, in the last decade, Raman spectroscopy proved successful as an elemental probe for glasses: different glass types can be easily recognized based on their spectrum [26][27][28] and valuable information on the network formers can be obtained via this vibrational spectroscopic technique. ...
... In addition to the stretching and bending massifs (1100 cm À1 and the 535 cm À1 , respectively), which suggest a mixed alkali composition, Ca 3 (PO 4 ) 2 is identified on the basis of its main vibration at 960 cm À1 . 19 It is likely that most of the calcium detected by hXRF is related to this compound, more than to its presence as a stabilizer inside the glass network. ...
... A different type of glass is found for the white glass bead Kindoki type 3 ( Figure 4, spectrum g). The main band of Ca 3 (PO 4 ) 2 is visible at 960 cm À1 , 19 in addition to the glass features. This bead type corresponds to other findings in the Congo and to beads in museums. ...
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Raman spectroscopy and X-ray fluorescence (XRF) analysis are commonly applied to archaeological objects as a fast and nondestructive way to characterize the materials. Here, micro-Raman spectroscopy and chemometrics on handheld XRF results were used to completely characterize beads found during archaeological excavations in the Congo. Metallic objects, organogenic materials, and glass beads were studied. Special attention was paid to the glassy materials, as they seem to be of European production. The matrix family and crystalline phases assemblage, as well as the results from principal components analysis on the elemental data, were used to define groups of beads of similar composition, and therefore probably of similar origin. This research project establishes the feasibility of this approach to archaeological glasses, and can be used to confirm and support the bead typologies used by archaeologists.
... Since then, copper red has been found in numerous areas and various time periods. Orange and red glass beads from the 5th-1st centuries BCE have been reported in South Asia (India, Thailand, and Sri Lanka) [13][14][15], with both Cu 2 O and Cu 0 colourations. Cuprite red was also very popular in enamel work in the Celtic period (4th-1st century BCE) [16] and the early Middle Ages in Europe [17]. ...
... Even if most cuprite coloured glasses, especially Roman ones, have very high lead contents, the exception to that rule deserves special attention. In fact, previous studies have shown that lead is not necessary to produce orange and red cuprite colours [15,23]. Some authors also described glasses coloured by cuprite with lead content below 10 wt% [14], including Roman glasses [20]. ...
... These two high copper content categories make it clear that cuprite formation is mainly favoured by the copper abundance, even though the presence of lead promotes the formation of cuprite and, more specifically, its crystalline growth. Figure 9. Review of copper and lead contents in archaeological samples, with information on the colouring particles and their shape, when avalaible [12][13][14][15]18,20,22,23,43]. ...
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This study aims at the characterisation of red and orange glass tesserae from the 4th-century Roman villa of Noheda (Spain). Due to the limited number of analyses available for such ancient materials, many questions remain unanswered about the production processes in the Roman period. Six samples were chosen for their hue variations, including two samples showing banded patterns of red and orange. Differences in copper speciation were investigated by X-ray absorption spectroscopy and compared with colour and compositional variations obtained by EPMA. The shapes and sizes of colouring crystals could be investigated using scanning and transmission electron microscope imaging. The brown-red colour is due to metallic copper nano-particles and corresponds to a low-copper and low-lead group usually described in the literature. The orange samples and bands are coloured by copper oxide Cu2O nanoparticles with remaining Cu+ in the glass and have greater contents of Cu. Compositional analyses reveal that the same base glass is used in the red and orange bands with additions of Cu, Sn, Pb and probable Fe. Furthermore, based on our results and on the literature review, a high-copper low-lead group of glasses highlights the variability of compositions observed in cuprite colours.
... Meanwhile, Raman spectroscopy has emerged as the most efective non-invasive method to identify chromophores, pigments and opaciiers in glasses and enamels (Bonneau et al., 2013;Colomban & Treppoz, 2001;Colomban et al., 2003;Ricciardi et al., 2009a;Ricciardi et al., 2009b;Prinsloo & Colomban, 2008;Prinsloo et al., 2011;Tournié et al., 2010Welter et al., 2007) as well as the types of glass matrix (Colomban et al., 2006a;Colomban et al., 2006b). his approach is widely used now (Baert et al., 2011;Caggiani et al., 2014;de Ferri et al., 2012;Gedzevičiūtė et al., 2009;Koleini et al., 2016a;Prinsloo et al., 2012). ...
... Naples Yellow solid solutions have been used in the Mediterranean area and Mesopotamia since Antiquity (Colomban, 2013) but the presence of Cr-Sn chromophore was not reported in the previous Raman studies. Table 2) -a) and b) are related to the composition of Mayotte beads. he colour of markers depends on the beads: a') and b') illustrate the literature data (Denbow et al, 2015;Dussubieux et al., 2008;Prinsloo and Colomban, 2008;Robertshaw et al., 2009Robertshaw et al., , 2010Welter et al., 2007). (Denbow et al., 2015;Dussubieux et al., 2008;Prinsloo and Colomban, 2008;Robertshaw et al., 2009Robertshaw et al., , 2010Welter et al., 2007). ...
... Table 2) -a) and b) are related to the composition of Mayotte beads. he colour of markers depends on the beads: a') and b') illustrate the literature data (Denbow et al, 2015;Dussubieux et al., 2008;Prinsloo and Colomban, 2008;Robertshaw et al., 2009Robertshaw et al., , 2010Welter et al., 2007). (Denbow et al., 2015;Dussubieux et al., 2008;Prinsloo and Colomban, 2008;Robertshaw et al., 2009Robertshaw et al., , 2010Welter et al., 2007). ...
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About hundred out of three hundred colored beads excavated from the necropolis of Antsiraka Boira (AB), in Mayotte Island (12-13th c.) were classified according to Wood’s morphological criteria and studied with a portable Raman spectrometer (532nm). Based on the recorded spectra, 22 beads were identified as representative and further analyzed in the laboratory with High-Resolution Raman spectrometers, using wavelengths of 458, 633 and 785nm. Additional SEM-EDS analysis was carried out on the surface and, sometimes, the bead cross-section. It turns out that white beads are made of aragonite and that almost all other beads have a soda glass matrix. Pyrochlore (yellow), amber/“Fe-S” (black), manganese oxide (black), copper metal nanoparticles (red), and Cu2+ ions (turquoise) chromophores were identified. Some red, yellow, black and turquoise beads also show the signature of chromium-doped tin sphene that could therefore be used as a marker. Most beads from the AB site can be classified as “Indo-Pacific”, revealing a similarity with the contemporary South African site of K2 (close to Mapungubwe). However, some red and black beads are similar to molten ceramic beads from the Vohemar Islamic necropolis (13-17th century AD, Madagascar Island). The on-site Raman analysis appears sufficient for the identification of chromophores and glass types.
... Meanwhile, Raman spectroscopy has emerged as the most effective non-invasive method to identify chromophores, pigments and opacifiers in glasses and enamels (Bonneau et al., 2013;Colomban & Treppoz, 2001;Colomban et al., 2003;Ricciardi et al., 2009a;Ricciardi et al., 2009b;Prinsloo & Colomban, 2008;Prinsloo et al., 2011;Tournié et al., 2010Welter et al., 2007) as well as the types of glass matrix (Colomban et al., 2006a;Colomban et al., 2006b). This approach is widely used now (Baert et al., 2011;Caggiani et al., 2014;de Ferri et al., 2012;Gedzevičiūtė et al., 2009;Koleini et al., 2016a;Prinsloo et al., 2011;Prinsloo et al., 2012). ...
... Table 2) -a) and b) are related to the composition of Mayotte beads. The colour of markers depends on the beads: a') and b') illustrate the literature data (Denbow et al, 2015;Dussubieux et al., 2008;Prinsloo and Colomban, 2008;Robertshaw et al., 2009Robertshaw et al., , 2010Welter et al., 2007). (Denbow et al., 2015;Dussubieux et al., 2008;Prinsloo and Colomban, 2008;Robertshaw et al., 2009Robertshaw et al., , 2010Welter et al., 2007). ...
... The colour of markers depends on the beads: a') and b') illustrate the literature data (Denbow et al, 2015;Dussubieux et al., 2008;Prinsloo and Colomban, 2008;Robertshaw et al., 2009Robertshaw et al., , 2010Welter et al., 2007). (Denbow et al., 2015;Dussubieux et al., 2008;Prinsloo and Colomban, 2008;Robertshaw et al., 2009Robertshaw et al., , 2010Welter et al., 2007). ...
Article
Full-text available
About hundred out of three hundred colored beads excavated from the necropolis of Antsiraka Boira (AB), in Mayotte Island (12-13 th c.) were classified according to Wood's morphological criteria and studied with a portable Raman spectrometer (532nm). Based on the recorded spectra, 22 beads were identified as representative and further analyzed in the laboratory with High-Resolution Raman spectrometers, using wavelengths of 458, 633 and 785nm. Additional SEM-EDS analysis was carried out on the surface and, sometimes, the bead cross-section. It turns out that white beads are made of aragonite and that almost all other beads have a soda glass matrix. Pyrochlore (yellow), amber/ " Fe-S " (black), manganese oxide (black), copper metal nanoparticles (red), and Cu 2+ ions (turquoise) chromophores were identified. Some red, yellow, black and turquoise beads also show the signature of chromium-doped tin sphene that could therefore be used as a marker. Most beads from the AB site can be classified as " Indo-Pacific " , revealing a similarity with the contemporary South African site of K2 (close to Mapungubwe). However, some red and black beads are similar to molten ceramic beads from the Vohemar Islamic necropolis (13-17 th century AD, Madagascar Island). The on-site Raman analysis appears sufficient for the identification of chromophores and glass types. Un ensemble d'une centaine de perles de la nécropole d'Antsiraka Boira (AB), Mayotte (xii e-xiii e siècles), considérées comme représentatives d'un lot de ~300, a été classé selon le système morphologique de Wood et analysé par spectroscopie Raman portable (532 nm). 22 perles représentatives ont été analysées par Raman avec différentes excitations laser (458, 633 et 785 nm) et SEM-EDS en surface, ou pour certaines sur section. Les chromophores ont été identifiés : pyrochlore (jaune), ambre/Fe-S (noir), oxyde de manganèse (noir), Cu 0 metal nanoparticules (rouge) et Cu 2+ ions (turquoise). Les perles blanches sont en aragonite (CaCO 3). Quelques perles rouges, jaunes, noires et une perle turquoise contiennent aussi le chromophore Cr-Sn sphène. Sa signature Raman, inattendue, pourra servir de marqueur. La quasi-totalité des matrices vitreuses sont sodiques. La comparaison des perles d'AB avec celles des sites de Mapungubwe/K2 (Afrique du Sud), met en évidence l'homogénéité du corpus comme pour K2, site contemporain de Antsiraka Boira et aussi classé « Indo-Pacifique ». Certaines perles rouges et noires, sont plus proches d'une céramique fondue que d'un verre, à l'instar de perles de Vohémar (XIIIe - XVIIe siècle, Madagascar). L'analyse au spectromètre Raman portable apparait suffisante pour identifier chromophores et types de verre.
... Micro-Raman analyses were, therefore, carried out on both anhedral and acicular inclusions dispersed into the glassy matrix, to ascertain their crystalline phases and verify the presence of cassiterite. Micro-Raman spectra acquired on the anhedral inclusions display bands at 136, 326 and 456 cm −1 (Fig. 8), matching those reported in the literature for the socalled lead-tin yellow type II (Welter et al. 2007;Zhao et al. 2013). Lead-tin yellow type II (PbSn 1-x Si x O 3 ) is a cubicstructured lead-tin silicon oxide that can show a variable stoichiometry: it can be either PbSnO 3 , Pb(Sn,Si)O 3 or 346 Archaeol Anthropol Sci (2019) 11:337-359 Fig. 6 a BSED image of G/V3 tessera. ...
... A band at about 634 cm −1 is always observed, being the one related to cassiterite (SnO 2 ). Though, an univocal characterisation cannot be stated due to the lack of the two other main bands of SnO 2 : 471 and 773 cm −1 (Bouchard and Smith 2003;Welter et al. 2007;Zhao et al. 2013). ...
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The paper discusses data concerning the secondary manufacture technology of a set of opaque coloured early Islamic mosaic glass tesserae from the qasr of Khirbet al-Mafjar (Jericho, Palestine). Archaeological contextualisation of the site had allowed attributing these finds to the Umayyad occupational phase of the building, and an in-depth study of the composition of the glassy matrix had provided evidence of a double supply of glass from Egypt and the Syro-Palestinian coast occurring in the production of the base glass intended to be used for the manufacture of mosaic tesserae. Here, a multi-methodological approach has been carried out to characterise colourants and opacifiers: visible reflectance spectroscopy (VIS-RS), optical microscopy (OM), scanning electron microscopy coupled with energy dispersion analysis (SEM-EDS), micro-Raman spectroscopy (micro-Raman) and X-ray diffraction (XRD) were performed on the opaque tesserae. Moreover, either optically stimulated luminescence (OSL) or thermoluminescence (TL) protocols for luminescence dating were applied on selected samples, with the aim of relating luminescence properties with the geochemical features of the glass tesserae, in the perspective of deepening the studies towards the absolute dating, an unquestionable help to the stimulating challenge of investigating ancient glass manufacture. Tin-based, phosphorus-based and copper-based opacifiers were identified, and the achieved results suggest the use of the same opacifiers and colouring agents regardless of the different base glass. Furthermore, data obtained by TL and OSL protocols revealed useful and stimulating potentialities these techniques could have in dating opaque glasses.
... In order to achieve precise compositional data on the crystals detected in the vitreous matrices, an integration between spectroscopic and diffractometric analyses is strongly recommended. m-Raman measurements directly performed on the anhedral and subhedral crystals clearly demonstrated that they are consistent with the Lead-Tin Yellow type II (Figure 34), for the bands at 68, 138, 327, and 455 cm −1 [55,91,92]. Lead-Tin Yellow type II (PbSn1-xSixO3) is a lead tin silicon oxide with a cubic structure, and it can show different stoichiometries-either PbSnO3, Pb(Sn,Si)O3 or PbSn2SiO3. ...
... Moving to acicular-shaped crystals, due to their extremely small dimensions, m-Raman measurements could be particularly challenging to be performed and the resulting spectra is hardly informative (Figure 36). A band at 632 cm −1 could be detected, related to cassiterite but not sufficient for a univocal identification, as the two other main bands of SnO2 were lacking-471 and 773 cm −1 [55,92,94]. Integration with diffractometric analyses could provide suitable support, allowing us to determine the presence of cassiterite, together with PbSnO3 in opaque green glasses ( Figure 37). ...
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This study aimed at laying the groundwork for a compendium on mineralogical phases responsible for the colors and opacity of ancient glasses, with specific reference to mosaic tesserae. Based on the awareness that a comprehensive database of these phases is currently lacking in the available literature, this compendium foresees two main objectives. The first scope was to set the basis for a well-structured database, as a reference point for scholars from different backgrounds for comparative and methodological purposes. The second goal was to provide insights on analytical methods that could be profitably used for achieving an in-depth characterization of coloring and opacifying inclusions; a tailored multi-analytical approach based on easily accessible and widespread techniques like OM, SEM-EDS, μ-Raman, and XRPD is proposed here. Micro-structural and compositional features of glass tesserae, where different types of crystalline phases were detected (Sb-based, Sn-based, Cu-based, Ca-phosphate-based) are presented in well-structured synoptic tables, following a summary on historical–archaeological information on their use.
... In recent years, many articles have been reported on the applications of Raman microscopes for the analysis of pigment grains in manuscripts and paintings. In addition, this method has also been used to analyze ancient materials ( Fig. 1) (Ziemann 2006), potteries ( Fig. 2) (Sandalinas et al. 2006), and ancient glass beads (Fig. 3) (Welter et al. 2007). One of the most important non destructive applications of Raman spectroscopy is the analysis of biological samples. ...
... One year later, Uysal et al. used Raman spectroscopy to detect adulterated butter with margarine. This investigation aimed to evaluate the performance of Raman (Welter et al. 2007) spectroscopy in comparison with other identification devices, such as principal component analysis (PCA), principal component regression (PCR), partial least squares (PLS), and artificial neural networks (ANNs). Consequently, Raman spectroscopy was considered a quick tool for detecting adulterated butter with margarine when compared with other devices (Uysal et al. 2013). ...
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Surface-enhanced Raman spectroscopy (SERS) is one of the most sensitive analytical tools. In some cases, it is possible to record a high-quality SERS spectrum in which even a single molecule is involved. Therefore, SERS is considered a significantly promising option as an alternative to routine analytical techniques used in food, environmental, biochemical, and medical analyzes. In this review, the definitive applications of SERS developed to identify biochemically important species (especially medical and biological) from the simplest to the most complex are briefly discussed. Moreover, the potential capability of SERS for being used as an alternative to routine methods in diagnostic and clinical cases is demonstrated. In addition, this article describes how SERS-based sensors work, addresses its advancements in the last 20 years, discusses its applications for detecting Coronavirus Disease 2019 (COVID-19), and finally describes future works. The authors hope that this article will be useful for researchers who want to enter this amazing field of research.
... The predominant characteristic of this glass is the large amount of copper that was added to produce the orange and red colours (Dussubieux 2001;Dussubieux and Gratuze 2003a;Lankton and Dussubieux 2006). The concentration of copper in this glass is generally more than 10 wt% and the colour is produced by the dispersion of cuprite in the glass matrix (Rösch et al. 1997;Welter et al. 2007). Iron is also generally relatively high in this glass. ...
... Copper-base phases: the Raman spectrum of the orange tessera from Milan (SA 1 1) shows a strong peak at ~220 cm -1 (Fig. 5e) recognized as cuprite (Cu 2 O [73,75]). Colour and opacity in the red and orange glass (SA_1_1, SA_3_12, HA_C_12) may result from the presence of cuprite crystals and/or metallic copper particles (Cu°). It is a well-known fact that the control of the copper oxidation state and the production of cuprite crystals require strong technical skills. ...
Article
Forty-two mosaic coloured/opaque “glass” tesserae from three sites (Milan, Italy; Durrës, Albania; Hierapolis, Turkey) situated in the Western and Eastern parts of the Roman/Byzantine Empire, dated between the 5th and the 9th centuries, were studied by optical microscopy, SEM-EDX and Raman microspectroscopy in order to investigate the nature of their pigments and opacifiers as well as the microstructure of glass ceramic materials. The Raman signatures of glass matrix and phases dispersed in the soda-lime glassy matrix showed the presence of six opacifiers/pigments. The use of soda ash glass in the tesserae from Durrës (post 8th c.) allows refining the mosaic debated chronology. The use of soda ash matrix glass together with the presence of calcium antimonates (Ca2Sb2O7 and CaSb2O6), pyrochlore solid solution/Naples’ yellow (PbSb2-x-ySnxMyO7-) and cuprite (Cu2O) or metallic copper (Cu°) in many samples show the technological continuity in a Roman tradition. However, the presence of cassiterite (SnO2) and quartz (SiO2) in one sample from the beginning of the 5th century, diverging from Roman technology, offers a chronological marker to identify newly (not re-used) produced tesserae.
... The predominant characteristic of this glass is the large amount of copper that was added to produce the orange and red colours (Dussubieux 2001;Dussubieux and Gratuze 2003a;Lankton and Dussubieux 2006). The concentration of copper in this glass is generally more than 10 wt% and the colour is produced by the dispersion of cuprite in the glass matrix (Rösch et al. 1997;Welter et al. 2007). Iron is also generally relatively high in this glass. ...
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This volume represents a comprehensive and essential collection of essays by Southeast Asia's leading archaeologists actively researching in the field
... Roman glass with lead is not uncommon but it was difficult to find comparative data for glass with such high lead concentrations. Welter et al. (2007) published the compositions from a few red beads from Oman that have high lead compositions and that overall match well the composition found for E42994. Manganese (b0.05%) and iron concentrations (N1.3%) are different from the concentrations for the same elements in E42994. ...
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This paper presents results of an interdisciplinary study of thirty-five bead artifacts found at Quseir port sites and presently stored in the Oriental Institute Museum at the University of Chicago. Many of the glass beads were ascribed to chronologically mixed contexts of the Early Roman Myos Hormos (1st–3rd c. A.D.) and Late Ayyubid-Mamluk Quseir el-Qadim (13th–14th c. A.D) periods. For both periods textual sources mentioned the overseas trade contacts of the Red Sea ports, and Carol Meyer (1992) and Peter Francis Jr. (2002) suggested the possible Indo-Pacific origin of some of these beads. While monochrome and decorated drawn and segmented, beads should point to the Mediterranean or Middle Eastern glass workshops, monochrome drawn and more or less rounded objects were considered by Peter Francis, Jr. as Indo-Pacific. By combining both macroscopic and compositional analyses, in particular, using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS), we present a bead typology and chronology of maritime bead trade subject within two main periods of Quseir occupation.
... Of course multi-analytical characterization yields complementary information and therefore a more complete interpretation of complex materials (see e.g. Welter et al., 2007). ...
... The bands of SnO 2 are detected at cm 21 : 474w, 633s, and 775w. [21][22][23][24] The bands of Pb 2 SnO 4 (Supporting Information Table 2) are in accordance with those found in the literature. 5,6,18,25,26 The calcined lead/ tin pigment obtained by Piccolpasso recipe (sample 14) was homogeneous and constituted by the compound Pb 2 SnO 4 . ...
Article
The aim of this study is to investigate the yellow pigments based on lead, tin, and antimony produced according to the ancient treatises, recipe books, and literary sources. The pigments considered in this study are lead/tin yellow type I (Pb 2 SnO 4), lead/tin yellow type II (PbSn 12x Si x O 3), lead antimonate or Naples yellow (Pb 2 Sb 2 O 7), and lead/tin/antimony yellow (Pb 2 SnSbO 6,5). Color was measured by X-Rite reflectance spectropho-tometer to investigate the chromatic characteristics of the produced pigments in relation to the recipes. The pigments were chemically characterized by scanning electron microscopy with energy-dispersive spectroscopy, and micro-Raman analysis to investigate the influence of reagents, temperature, and melting modalities in the compositions of the produced powders. A part of the study was devoted to the study on the use of these yellow pigments in the art history especially concerning the modus pingendi of Italian artists between 14th and 18th century. The results of this study highlighted the possibility to obtain pigments with different colors and compositions according to the reagents, to the temperature, to the melting modality, in particular if single or double firing was used.
... The bands of SnO 2 are detected at cm 21 : 474w, 633s, and 775w. [21][22][23][24] The bands of Pb 2 SnO 4 (Supporting Information Table 2) are in accordance with those found in the literature. 5,6,18,25,26 The calcined lead/ tin pigment obtained by Piccolpasso recipe (sample 14) was homogeneous and constituted by the compound Pb 2 SnO 4 . ...
Conference Paper
The aim of this study is to investigate the yellow pigments based on lead, tin and antimony produced according to ancient treatises, recipe books and literary sources. The pigments considered in the present study are lead/tin yellow type I (Pb2SnO4), lead/tin yellow type II (PbSnO3), lead antimonate or Naples yellow (Pb2Sb2O7) and lead/tin/antimony yellow (Pb2SnSbO6,5). Colour was measured by X-Rite reflectance spectrophotometer to investigate the chromatic characteristics of the produced pigments in relation to the recipes. The pigments were chemically characterized by scanning electron microscopy with energy dispersive spectroscopy, and micro-Raman analysis in order to investigate the influence of reagents, temperature and melting modalities in the compositions of the produced powders. A part of the work was devoted to the study on the use of these yellow pigments in the art history especially concerning the modus pingendi of Italian artists between 14th and 18th century. The results of this work highlighted the possibility to obtain pigments with different colours and composition according to the reagents, to the temperature, to the melting modality. Generally the pigments prepared according to the ancient recipes are mixtures of different compounds. The study on the use of these pigments by artists highlighted that the choice of the yellow typology was made on the base of the colour or the availability from the suppliers, even if the artists were conscious of the chemical-physical characteristics of the lead/tin/antimony yellow pigments.
... MgO 超过 1%。以往研究认为中国古代钾玻璃中钾 的来源主要有硝石和草木灰 [4,9,11] [7,[9][10] 。其中,m-K-Ca 亚类钾玻璃(CaO 含量 在 3%~6%, Al 2 O 3 多低于 1%)仅在泰国的班东达潘 (Ban Don Ta Phet)有发现, 时间为公元前 4~2 世纪 [23] 。 硅 酸 盐 学 报 · 1002 · 2013 年 中国各地包括广州发现的汉代至魏晋时期的钾玻璃 基本都属于 m-K-Ca-Al、m-K-Al 亚类,但各地区中 每个亚类玻璃所占的比例不同。例如,在新疆各地 发现的钾玻璃均为 m-K-Ca-Al 亚类 [7] 。m-K-Ca-Al 和 m-K-Al 亚类钾玻璃在亚洲各地区的广泛发现 [9,24] , 说明在公元前 4 世纪至公元 5 世纪期间,亚洲可能 存在多个钾玻璃的制作中心。对广西出土汉代钾玻 璃的研究表明,在汉代交州刺史部所属地域可能是 m-K-Ca-Al 和 m-K-Al 亚类钾玻璃的一个制作中心 [10] 。 广州发现的汉代钾玻璃中有一部分应为交州刺史部 或临近地区制作。铜红珠的制作工艺相对复杂,中 国陶工是在公元 7-10 世纪才开始制造铜红釉,这 比中东地区晚了很多 [25] 。图 2 中 II 区椭圆形区域内 的 3 件铜红珠属于舶来品。 采用 SnO 2 和 PbSnO 3 作为乳浊剂/着色剂的钠钙 玻璃在公元前 2 世纪左右在欧洲出现,并在公元 4 世纪后广泛应用于罗马和拜占庭玻璃制作 [20] ;公元 4~8 世纪期间,欧洲和西亚地区也将锡基化合物广 泛应用于伊斯兰玻璃、壁画颜料、珐琅器和瓷釉的 制作 [19,[26][27][28] 。使用 SnO 2 和 PbSnO 3 作为玻璃乳浊剂/ 着色剂的工艺,可能由欧洲和西亚传播至南亚和东 南亚地区 [13,21] 。目前认为广州汉墓出土的 m-Na-Al 玻璃和钠钙玻璃可能分别由南亚和西亚地区传入。 从分析的广州出土汉代玻璃制品的时间上看可 见:铅钡玻璃最早为西汉早期(耳塞 GAZ-40),铅玻 璃最早为西汉中期,两种玻璃在东汉时期均有发现; 钾 玻 璃 最 早 为 西 汉 中 期 ( 如 样 品 GAZ-37-2 、 ...
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In this paper, the chemical compositions of 46 ancient glass samples such as monochrome beads and ear pendants were analyzed using a portable energy dispersive X-ray fluorescence spectrometer. These glass artefacts, which were all unearthed from Guangzhou, Guangdong province, were dated from early Western Han Dynasty to the Eastern Han Dynasty. The effect of surface weathering on the quantitative analysis was discussed. It was found that these glass artefacts of the Han Dynasties could be divided into PbO–BaO–SiO2, PbO–SiO2, K2O–SiO2 and Na2O–CaO–SiO2 glass systems. Among them, the Na2O–CaO–SiO2 glasses were first determined in the tombs of the Eastern Han Dynasty. Based on the contents of CaO, Al2O3 and weight ratio of trace elements Rb to Sr, the potash glasses, which took the greatest ratio of those glasses analyzed, were further classified into some sub-types. In addition, some of the glass samples were analyzed using a laser Raman spectrometer. Crystalline Cu2O and PbSnO3, which were used as colorants and opacifiers, were identified. Referred to the archaeological research results, these ancient glasses could be considered to be from China, South & Southeast Asia and West Asia.
... The Raman analysis of sample XJ05-9A indicates that the high SnO 2 content is due to the existence of crystalline cassiterite. By focusing the laser beam directly on the bright microcrystals in the glassy matrix, one can easily identify the typical Raman bands at about 633 and 775 cm -1 (Colomban et al. 2001;Welter et al. 2007), as shown in Figure 7. Crystalline phases, either the residue of raw materials or those formed by a devitrifying process, were also identified. The existence of quartz particles in several samples, which can be attributed to the residue of raw materials during the manufacturing process, was confirmed by both Raman spectroscopy and SEM-EDS analyses. ...
Article
A total of 33 ancient glass beads unearthed from the Kizil reservoir cemetery and Wanquan cemetery in Xinjiang are studied using Raman spectroscopy, scanning electron microscopy with energy-dispersive spectrometry (SEM–EDS) and other methods. The detailed study of the glassy matrices, the crystalline inclusions and the microstructural heterogeneities for these glass beads has revealed some valuable information to help in the understanding of their possible manufacturing technology and provenance. At least two different types of glass were present in the two cemeteries. For the first time, antimony-based colourant/opacifier—for example, Pb2Sb2O7 or CaSb2O6—was systematically identified in some beads of plant-ash type soda–lime glass dated to about 1000–500 bc. The limited number of potash glass beads from the Kizil reservoir cemetery, which were dated to about 500–300 bc, used tin oxide as an opacifier. The diverse resources of the soda–lime and potash glasses indicate the existence of a complex trade network between China and the West much earlier than the Western Han Dynasty.
... The use of X-Ray diffraction for the study of historical/archaeological glasses is still sporadically attested, especially for non-invasive investigation purposes. Previous studies have focused on beads from the Sultanate of Oman and Sri Lanka (Rösh et al., 1997;Welter et al., 2007), Mosaic Tesserae from the monasteries of Daphi and Hosios Loukas in Greece (Arletti et al., 2010a), Iron Age beads from Northern Italy (Arletti et al., 2010b), Ca-antimonate in Roman glasses (Lahlil et al., 2010), mosaic Tesserae from St. Peter in Rome (Arletti et al., 2011b), archaeological red glasses from China (Zhu et al., 2012) and Iron-age findings from the Treviso province (Olmeda et al., 2015). X-ray Fig. 1. ...
Poster
Studies carried out in the last decades defined that two main ethnic groups existed along the Italian Adriatic coast from the beginning of the Iron Age to the Romans conquest: Japigi and Sabelli, which were in turn divided into various tribes, including Picenes, living in the current coastal area of the Marche and of the northern Abruzzo regions between the 1st millennium B.C. and the 3rd century A.D. The excavations of two Picene necropolises in Novilara (9th-7th century B.C, PU) and Matelica (9th-6th century B.C., MC) uncovered various grave goods including many colored glass, shell and bone-based beads. A non-invasive characterization these beads has been performed by means of analytical techniques such as Reflectance and Raman spectroscopy and X-Ray diffraction. Raman spectroscopy resulted particularly useful in the characterization of shell and bone based beads, displaying the typical spectra of calcite and Ca-phosphate, respectively, parallel reflectance spectroscopy gave information about the use of different chromophores in blue glass beads: as expected spectra of the darker samples contain the typical features of tetrahedral Co2+ ions, while data obtained from the two light blue beads available, coming from the Matelica necropolis, showed no traces of this metal but only the spectral profile deriving from the presence of Cu2+ ions. As known from literature, turquoise glass was commonly used during the Bronze Age, while cobalt started to be employed as a colorant during the Final Bronze Age in association with copper and then became the dominant metal to obtain dark hues due to its high colouring efficiency. Both Reflectance and Raman Spectroscopy allowed the identification of hematite as the colouring agent of the only red bead available, coming from the Novilara necropolis. This is a very peculiar result, since no literature data have been reported so far, to the best of our knowledge, about the use of hematite in glassy beads dated to the Iron Age. White and yellow samples were mainly studied by XRD: in both cases the use of traditional opacifiers such as Ca and Pb antimonates was demonstrated. Yellow samples in particular displayed the presence of lead pyroantimonate (Pb2Sb2O7), whose diffraction peaks could be well distinguished over the broad glass structure; on the contrary, the collection of patterns from white samples, exhibiting a black surface decorative coating, gave results that were more difficult to interpret.
... [17][18][19] Cuprite. The Raman spectrum collected from the H3 orange tessera (Fig. 3(F), Table 1), shows a strong peak at 218 cm À1 , attributable to the characteristic vibrational mode of cuprite Cu 2 O, [29,30] revealed also by the diffraction pattern (Fig. S3(A)). ...
Article
Several glass mosaic tesserae were recovered during the archeological excavation of the thermal baths at the ‘Villa dei Quintili’ in Rome and dated to the second century AD. This work reports the results of an archeometrical investigation performed, through a multi-technique approach, on 19 colored opaque tesserae. The aims of the study were (1) the characterization of coloring and opacifying agents used for the production of the glass tesserae and (2) the definition of the technological processes involved. Colorimetric measurements allowed us to classify the tesserae in color groups, while the glassy matrix and the dispersed crystallites were characterized in detail through micro-Raman spectroscopy, field emission scanning electron microscopy with energy dispersive X-ray spectroscopy, laser ablation-inductively coupled plasma-mass spectrometry, and X-ray powder diffraction analyses. Most of the glass shows the typical soda-lime-silicate composition (except for the orange and red tesserae). Raman results and elemental analysis prove the use of Sn–Pb antimonates to create yellow glass and of Ca-antimonates for the white tesserae. A mixture of Sn–Pb antimonates and copper ions was used to obtain the emerald green color, while Ca-antimonates were employed in both copper-colored and cobalt-colored blue glass to obtain different shades (blue-green, dark, and light blue). X-ray powder diffraction analyses reveal the presence of metallic copper (Cu0) and Cu2O particles (cuprite) in red and orange tesserae, respectively. These results confirm the high technological level reached by the glassmakers of the Imperial Age.
... The use of X-Ray diffraction for the study of historical/archaeological glasses is still sporadically attested, especially for non-invasive investigation purposes. Previous studies have focused on beads from the Sultanate of Oman and Sri Lanka (Rösh et al., 1997;Welter et al., 2007), Mosaic Tesserae from the monasteries of Daphi and Hosios Loukas in Greece (Arletti et al., 2010a), Iron Age beads from Northern Italy (Arletti et al., 2010b), Ca-antimonate in Roman glasses (Lahlil et al., 2010), mosaic Tesserae from St. Peter in Rome (Arletti et al., 2011b), archaeological red glasses from China (Zhu et al., 2012) and Iron-age findings from the Treviso province (Olmeda et al., 2015). X-ray Fig. 1. ...
Article
A totally non-destructive approach was employed to characterize beads from two Picene necropolises (Novilara-PU and Crocefisso-Matelica-MC) dating back to between 9th and 6th centuries B.C. Investigations were carried out principally by means of Reflectance Spectroscopy determining Co2+, Cu2+ and Fe3+ as the main chromophores, and by Raman Spectroscopy to distinguish samples realized with other materials, in particular bones and shells were recognized. Furthermore, Raman spectroscopy identified hematite as a coloring phase in the unique red bead discovered as unmelt crystals in blue and yellow beads. Additionally, X-Ray Diffractometry investigations indicated Ca-phosphates, bindhemite and the less common brizzite, as opacifiers in white and yellow beads, while chemical data collected through X-Ray Fluorescence evidenced differences between findings from the two localities and/or within the same site. Beads were found to belong to the Low Magnesium Glass (LMG) and High Magnesium Low Potassium (HMLK) classes with most blue beads being comprised of cobaltiferous alum salts and a relatively impure sand, and a calcareous sand having been used for all other analyzed beads. Finally, differentiations performed on the basis of MgO amounts tended to indicate the samples from Crocefisso as being more similar to Bronze Age compositions than the Novilara ones which are closer to typical Iron Age proportions. In addition, high amounts of lead have been detected in all the yellow beads, but they could be positively correlated to Sb2O3 only for samples recovered in the Novilara necropolis, thus indicating the use of lead antimonates as coloring agents.
... Its presence is reported mostly in natron glass or potash lime silica glass from the eastern part of the Mediterranean Sea and northern Italy before early 1st millennium CE (Towle and Henderson, 2007;Marii and Rehren, 2009;Neri et al., 2017). Previous research reporting bone ash in high alumina glass from around the Indo-Pacific region is found in two white glasses from Sri Lanka, dated to 300 BCE -900 CE (Welter et al., 2007), but the Al 2 O 3 content is lower in the Sri Lankan glass (<5 wt%) than in samples from Taiwan (~8-10 wt%). The Sri Lankan samples also show greater CaO (7.5 wt%) compared to the Taiwanese ones (<2 wt%). ...
Article
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Archaeological excavations at Guishan in the southern end of Taiwan have recovered more than a hundred glass beads dating to mid-1st millennium CE. This research investigates the exchange of glass beads between Guishan, eastern Taiwan and Southeast Asia, by analysing the styles, chemical composition and microstructure of 64 glass beads from Guishan, using SEM-EDS, EPMA and LA-ICP-MS. The findings suggest that beads with an m-Na-Al glass and v-Na-Ca composition are the most common, supporting evidence for bead exchange between Guishan and Southeast Asia, originated in South Asia and Western Asia. Furthermore, most m-Na-Al glasses were coloured by copper, and different types of copper-based additives may have been used for different colours, indicating the beads may be derived from multiple production centres or workshops via Southeast Asia. Conversely, the glass bead compositions suggest that glass bead exchange between other contemporary sites in Taiwan is less evident at Guishan, except for one type of yellow glass bead containing bone ash which is different. This bone-ash containing yellow glass at Guishan is firstly identified in Iron Age Taiwan as well as around the South China Sea region. Its counterparts are also found from archaeological sites in southeastern and coastal eastern Taiwan, which might indicate small scale glass bead exchange. This evidence together suggests a dynamic glass bead exchange network between Guishan, eastern Taiwan, Southeast Asia and beyond.
... Thus, in recent years, many articles have been published on the use of a Raman microscope for pigment analysis of manuscripts and paintings. Besides, this method has been applied to analyze ancient inscriptions [11], potteries [12], and ancient glasses [13]. One of the most important non-destructive applications of Raman spectroscopy is the analysis of biological samples. ...
Article
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Raman spectroscopy is an important method for the identification of molecules that is widely used to determine the chemical and structural properties of various materials. Many materials have special Raman spectra so that this phenomenon can it has become an effective tool for studying the structural and chemical properties of molecules. Since Raman spectroscopy can provide accurate information on the chemical and structural properties of biological compounds, this method is used in the field of science. Vital and especially in biological and medical studies is rapidly expanding. Raman is inherently weak and sometimes masked by noise and fluorescence. As a result, the study of low-concentration molecules is not feasible and the need to amplify the Raman scattering signal is clearly felt. . One of the efficient methods for studying low and even single molecular concentrations is the Surface Enhanced Raman Scattering (SERS) method. It uses gold, silver, copper and noble metal nanoparticles to enhance the Raman scattering signal. . SERS has been rapidly expanding over the past four decades, as applications for recognition in the fields of chemistry, materials sciences, biochemistry and biosciences are rapidly expanding. Advances in the manufacture of SERS-based biosensors are a major breakthrough in the detection of biological materials in which the electromagnetic field (effect) molecule is affected by the external field, this larger substitute field due to electromagnetic resonance near the metal surface is formed. Mechanisms of electromagnetic field (field effect) amplifiers mainly contribute to the development of SERS, which includes the study of detection performance, direct and indirect fabrication methods for the identification of biological and chemical analytes, Applications of biosensors, amplifiers, and SERS-based biosensor structures to detect biomolecules are briefly described.
... Cuprite yields Raman bands at 147, 215, 494 and 623 cm −1 which are often only visible as weak bands or shoulders (cf. Fig. 2a) [79,80]. Massicot and its polymorph litharge are strong Raman scatterer. ...
Article
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Article downloadable Open Access from Heritage Science - Cellulose ethers, like methyl cellulose (MC) or hydroxypropyl cellulose (HPC), are widely used in conservation. They also occur as additives and rheology modifiers in various products like dispersions or gels. Do such products release harmful volatile organic compounds (VOC) during their accelerated aging? A mass testing series utilizing the Oddy test of 60 commercial cellulose ethers ranks the products in safe for permanent use (P, no corrosion), only for temporary use (T, slight corrosion), and unsuitable at all (F, heavy corrosion). Results show that 55% of the products passed the test whereas 33% are for temporary use as slight corrosion occurred on at least one metal coupon and only 11% failed the Oddy test. Raman measurements of the corrosion products identified oxides like massicot, litharge, cuprite, and tenorite among carbonates (hydrocerussite, plumbonacrite), and acetates like basic lead acetate, lead acetate tri-hydrate as well as lead formate as main phases. For example, commercial, industrial Klucel ® G (HPC) scored a T rating through slight corrosion on the lead coupon. Basic lead acetate among other phases indicates the presence of acetic acid. Additional measurements of the sample with thermal desorption GC-MS utilizing the BEMMA scheme confirm the high acetic acid outgassing and reveal the presence of a small amount of formaldehyde.
... As far as the orange, yellow-orange, and yellow colors are concerned (points S3 S13, S24, S26, S27), Figure 6 shows a representative photomicrograph, together with corresponding µ-Raman spectrum, collected on a yellow-orange micro-fragment ( pled at point S13) of the painting. Based on a comparison with literature [23][24][25][26], the low-frequency contributions centered at~252 cm −1 (A 1g ),~288 cm −1 (E g ) and~347 cm −1 (E g ) can be ascribed to the presence of vermilion (HgS), confirming our previous XRF and EPMA-EDS results. Such a compound, obtained by powdering the cinnabar mineral, assumed remarkable relevance as an artist's red paint since Roman times, sometimes combined with burnt sulfur, despite its high cost and toxicity. ...
Article
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The present paper illustrates the results of a diagnostic investigation performed on the oil on canvas painting “The Glory of St. Barbara” (1680–1688) by Mattia Preti. The painting is located inside the St. Barbara Church in Taverna (Catanzaro, Italy), the city that gave birth to the artist. In situ, non-invasive studies, by applying X-ray fluorescence (XRF) spectroscopy, along with laboratory micro-destructive analytical investigations, by employing electron probe microanalyses (EPMA) coupled with energy-dispersive spectrometry (EDS) and micro-Raman (µ-Raman) spectroscopy, were combined to retrieve the color palette and identify the painting technique and style of the famous master. As a result of this multi-scale characterization, an extraordinary pictorial technique was revealed, enriching knowledge about one of the oldest pictorial traditions outlined by Mattia Preti, and solving doubts still existing about many of his investigated artworks. Moreover, the achieved results represent useful and essential tools to address management issues of the artwork, by providing valuable information for planning and monitoring future restoration interventions of the canvas.
... Micrometric crystals with either anhedral or subhedral habitus have been detected, mainly in the bands (Figure 11d), and EDS spot measurements demonstrated that the crystals were mainly made of lead and tin (Figure 11e). The micro-Raman spectra acquired on the crystals (Figure 11f) showed bands at 68, 138, 327, and 455 cm −1 , consistent with lead-tin yellow type II [83][84][85], a cubicstructured lead-tin silicon oxide that can show different stoichiometries [either PbSnO 3 , Pb(Sn, Si)O 3 , or PbSn 2 SiO 3 ]. Comparison between the Raman spectra of pure PbSnO 3 and PbSn 1−x Si x O 3 was unfeasible, as a signature of PbSnO 3 alone is not reported in the literature. ...
Article
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The connection between Umayyad and Byzantine mosaic manufacture is a debated issue: on the one hand, Arab sources report that Umayyad caliphs received craftspeople and materials to adorn religious buildings from the Byzantine emperor; on the other hand, the reliability of these texts has long been disputed among scholars, and other possible influences have been hypothesised. Was early Islamic mosaic manufacture related to Byzantine tradition and to what extent? Were materials and artisans gathered from Byzantium and/or territories under the Byzantine control? Based on a multi-analytical approach, glass tesserae from Khirbat al-Mafjar, the Great Mosque of Damascus, and the Dome of the Rock have been analysed. Results speak of a tale of two legacies, demonstrating that, parallel to a continuity with the manufacture of glass tesserae in the late antique Levant—pointing, more specifically, to a re-use of materials from abandoned buildings—legacies other than Byzantine occurred. It emerged that Egypt definitively played a role in mosaic making during the Umayyad caliphate, acting as a supplier of skilled artisans and materials.
... Current interest in these researches focuses on control of size, shape and composition of nanoparticles to manipulate their physicochemical properties. 7,8 Cuprous oxide (Cu 2 O) is a p-type semiconductor which has potential applications in catalysts and photocatalyst, 9,10 solar cells, 11 pigments, 12 and also has been used as a fungicide an antibacterial agent. 13,14 Cu 2 O crystals with different morphologies have been prepared by chemical reduction approaches in which Cu 2+ ions convert to Cu + with a reducing agent and several successful methods have been reported for the production of Cu 2 O. [15][16][17][18] Some papers have reported the green and convenient biosynthesis of different metal oxide nanoparticles such as Fe 3 O 4 , 19 CuO, 20 TiO 2 , 21 ZnO, 22 Cu 2 O/CuO 23 and Ag/Cu 2 O, 24 which were produced using natural products. ...
Article
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Biocompatible syntheses of Cu2O nanoparticles are relatively low compared to some other reported metal oxides due to their low stability and requiring more carefully controlled synthetic conditions. In the present study, the efficiency of three brown algae (Cystoseira myrica,Sargassum latifoliumandPadina australis) extracts collected from the Persian Gulf was evaluated in the biosynthesis of Cu2O nanoparticles. A fast and simplified synthesis of Cu2O nanoparticles with average size between 12 and 26 nm was successfully achieved through an eco-friendly method using the aqueous extracts ofSargassum latifoliumandCystoseira myrica. Whereas, under the same reaction conditions usingPadina australisextract no Cu2O nanoparticles were produced, and unexpectedly, the results approved the formation of spindle shaped CaCO3with average sizes of 1-2 μm in length and 300-500 nm in width. Structure, morphology and composition of the as-prepared products were characterized by XRD, FT-IR, UV-vis, TEM and FESEM analysis. This work confirms that the biomolecules present in algae have the ability to affect particle size, morphology, composition, and physicochemical properties of the synthesized particles. The Cu2O nanoparticles prepared in this study were stable and exhibited efficient antibacterial and anticancer activity. This biosynthesis technique can be valuable in environmental, biotechnological, pharmaceutical and medical applications.
... The green color of glasses may result from a combination of a Cu 2+ blue glass matrix with yellow pigments. [23] Some addition of Cu to the glass recipe turns the color of yellow beads to green. [24] The presence of Fe 2+ ions gives a blue color to the glasses due to their broad absorption bands that could extend to the visible region at around 1,100 nm, whereas the Fe 3+ ions are responsible for yellow color because of their absorption bands at around 380, 420, and 440 nm; when the ratio Fe 2+ /Fe 3+ diminishes, such a color moves to green. ...
... The cited glass technology required the capability to strictly control the redox conditions during firing, since the formation of monovalent copper inside the glass matrix could be obtained either by adding proper reducing agents (such as iron) and/or tuning the furnace atmosphere using a limited range of oxygen partial pressures [106]. Furthermore, the addition of PbO to the recipe of copper-red glass was often used since PbO increases the density of the flux thus providing a better distribution of copper into the glass matrix, resulting in an intense and homogenous red color [111]. In addition, the use of copper alloy scale as a source of copper, known to be a technology employed in the production of Roman mosaic red tesserae in Italy [112,113], could be discarded due to the low amount of tin found in 15117RV. ...
Article
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The archaeological excavations at Villa San Pancrazio (Taormina, Italy) are bringing to light a vast Roman-Imperial residential quarter featuring luxurious dwellings decorated with wall paintings and mosaic floors, pointing it out as one of the most significant archaeological sites of the city. The polychrome and black and white mosaics recovered date back to the middle Imperial period , during the 2nd century AD. This work deals with the first archaeometric investigations of the materials employed for the tesserae production with the aim of elucidating the mineralogical composition and obtaining analytical evidence that can contribute to extracting information related to their production technology. For that purpose, a non-invasive methodology, based on micro energy dispersive X-ray fluorescence (μ-EDXRF) spectrometry and Raman spectroscopy, was used to characterize a wide selection of stone, ceramic and glass tesserae. Chemometric tools were exploited to manage the large set of elemental data collected on black and white lithic samples, providing essential clues for the subsequent investigations. The results evidenced the employment of natural litho-types (calcareous sedimentary, dolomitic and volcanic) local and imported, and also artificial materials , such as ceramic made firing magnesium-rich clays, soda-lime-silica glasses made with different opacifying and coloring agents (such as calcium antimoniate, cobalt and copper).
... gold ruby red or silver yellow nanoparticles) that grew up within the glass with specific size and morphology or to semiconducting inorganic pigments (e.g. red Cu 2 O, yellow CdS) encapsulated in the vitreous matrix [3,4]. Absorption properties are governed by surface plasmon resonance phenomena in the former case and by the promotion of electrons from the valence band to the conduction band in the latter case. ...
Article
Opal glasses fabricated by Arc (Arques, France) are glass-ceramics that consist of a glassy matrix mainly constituted of silicon dioxide with well crystallized fluoride compounds as inclusions. These later (ca. 8 vol%) play the role of light scattering centers leading to the well-known milky feature of the commercialized glassware, dinnerware products. Their overall chromatic characteristics strongly depend on few parameters (e.g. the refractive indexes of the glass and the ceramic(s), the concentration of inclusions, their mean size, the surface roughness of the article, etc) that have to be determined and controlled during the manufacturing process to end at the product with the desired optical properties. Using a transfer matrix formalism, the 4-flux method can indeed be used to anticipate the transmittance and reflectance of an object for different set of parameters. The impact of each aforementioned parameter on the color rendering will be here separately discussed, and simulations will be confronted to experimental data to assert their validity and their interest to the genesis of new products with targeted optical properties.
... Lead glasses have been used throughout history to produce small objects such as beads, mosaic tiles, or rings, [1][2][3][4][5] as well as in the decoration of rings, bracelets, or small vessels. [6][7][8][9][10][11] These glasses generally are opaque due to the precipitation of lead antimonate or lead stannate during the glass batch and the annealing. ...
Article
Some historical glasses (lead‐wood ash glasses, lead‐crystal glasses…) are silicate glasses with high content of lead and potassium. This work presents the evaluation of the chemical stability of high‐lead glasses in a high relative humidity atmosphere and as result of aqueous immersion. In both situations, the alteration mechanism begins with the lixiviation of alkali metal and lead ions, followed by the hydrolytic attack of the silica glass network. According to the results, the glasses with a higher content of lead show the fastest degradation due to their higher hygroscopicity. Environmental CO2 can be dissolved in the adsorbed water and favor the formation of intermediate degradation compounds.
... Of course multi-analytical characterization yields complementary information and therefore a more complete interpretation of complex materials (see e.g. Welter et al., 2007). ...
Chapter
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The chapters contributed to the volume recognize the important and diverse contributions of mineralogy to the valorization, characterization, interpretation and conservation of cultural heritage. The book focuses on examples of materials and methodological issues rather than technical/analytical details. We have attempted to deal with the cultural heritage materials in chronological order of their technological developments, to relate them to past human activities, and to highlight unresolved problems in need of investigation.
Conference Paper
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We report on application of Ag nanoparticles in high sensitive surface-enhanced Raman spectroscopy to detect low quantity of art pigments.
Chapter
Glass has not only been produced to make glass artefacts. The largest range of glass compositions was prepared by potters in order to coat pottery with glazes and to apply complex enamelled coatings to make porous ceramic bodies impermeable or for decorative purposes. Enamels have also been deposited on metals since the earliest times. All of these uses require the preparation of (coloured/colourless) glass compositions ranging from a high silica content to a low melting lead–rich glass with melting temperature below 600°C. The controlled modification of the three dimensional Si–O network by replacement of Si4+ covalently bonded atoms by non–covalently bonded atoms, hence decreasing the number of Si–O bridges and the connectivity of the network modifies the ionicity/covalency of the polymeric (Si–O–Si–O–)n network and its degree of polymerization. We will first address the fundamentals of vibrational spectroscopy, then the problem of defining the best vibrational unit to understand the structure of amorphous silicates and the associated models used to describe the vibrational signature and to extract parameters related to composition, production technologies, etc. Attention will be paid to the modification of the Raman signature as a result of glass weathering. If the laser wavelength falls within some electronic levels, in other words if the colour of the laser corresponds to the colour absorbed by the matter, the resonance Raman spectroscopy allows studying pigments/chromophores/nanoparticles and their site), specifically. We will consider the advantages and drawbacks of modern portable Raman instruments and list some useful databases. Finally some case studies (stained glass, glass artefacts and glazed pottery) will illustrate the potential of Raman scattering to discriminate between original artefacts and forgery or even identify later embellishments.
Chapter
IntroductionHow to Discriminate Between Genuine Artifacts and Copies and FakesOn-Site Measurements and ProceduresCase StudiesConclusions References
Chapter
The basis of the generation of characteristic Raman spectral signatures of glass, pottery and enamelled artefacts is considered and the theory underlying the structural changes taking place in glassy and crystalline silicates. A historical survey is undertaken of glass compositional changes through the ages and the Raman spectral fingerprints that are available. The resonance Raman effect and its application to glass structural studies. Glass weathering mechanisms and their correlation with Raman spectral signatures. Use of mobile Raman spectroscopy. The recognition of technological milestones in glass production through eth ages. Case studies of coloured glasses and trade glass beads.KeywordsGlassPotteryEnamelsGlass trade beadsRaman spectral signatures of glassWeathering of glassBlueGreen and yellow coloured glasses
Article
Micro-Raman spectroscopy (RS) and optical microscopy (OM) under visible (VIS) and ultraviolet (UV) light were applied to characterize the pigments, state of conservation, and painting techniques used in the 17th century panel painting ‘Servilius Appius,’ attributed to Isaac van den Blocke. This Golden Age work of art is located at the Gdańsk History Museum. Briefly, individual layers of six samples from different parts of the aforementioned painting were analyzed. A rich palette of white, yellow, red, blue, and black pigments were identified using micro-Raman spectroscopy. Optical microscopy was also employed to observe and analyze these layers. The obtained results were compared with the art history knowledge of the painting. Consequently, these studies enabled precise characterization of the type of lead tin yellow, the admixture of pigments used in the painting layers, and the type of ground layers, as well as the determination of the pictorial technique used in the process of creating this work of art.
Article
Structural engineering of nanocrystals is of great importance to control the properties of semiconductor oxides. Here, we present a mild wet chemical reduction route to obtain a sub-micron porous jujube-like Cu2O hierarchy structure. Sodium dodecylbenzene sulfonate (SDBS) is crucial in structural regulation and it acts as a soft template and a capping agent. The jujube-like particle consists of crystal grains less than 10 nm in size as verified by transmission electron microscopy (TEM) and X-ray diffraction (XRD). A set of time control experiments were carried out to study the evolution of the jujube-like structure. Interestingly, we found that altering the amount of added HCl resulted in a size-tuning effect of changing the size of the particles from approximately 300 to 900 nm. Based on these results, we propose a possible growth-etching competition mechanism to explain the formation of the hollow interior and its porous nature, which also agrees with the sizing-tuning effect. The optical properties were analyzed using Raman spectroscopy. By comparison with a conventional sub-micron solid polyhedral we found a novel Raman property for the porous jujube-like Cu2O. Our research complements the library of Cu2O Raman spectra, which is meaningful for the nondestructive examination of pigments on the surface of antiques by Raman techniques.
Article
Two ancient green Chinese Pb-Ba glass (Qin and Han dynasties) were studied with Raman microspectroscopy, scanning electron microscopy, and energy dispersive X-ray spectrometry. Some needlelike silicates were found in the samples and inferred as BaSiO3, BaSi2O5, and PbSiO3 according to the results of energy dispersive X-ray spectrometry analysis. Then BaSiO3, BaSi2O5, and PbSiO3 were synthetized in laboratory in order to obtain their Raman spectra. Through comparative study, the needlelike silicates in the ancient Pb-Ba glass samples were proved to be PbSiO3, BaSiO3, and Al2O3. According to the ternary phase diagram analysis, a mechanism of local element enrichment was put forward for the barium silicate needlelike silicates (by-products) formation in the ancient Pb-Ba glass. Copyright © 2014 John Wiley & Sons, Ltd.
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Nondestructive X-ray analyses were applied to ancient Egyptian copper-red glass artefacts to investigate the coloring mechanism of the glass and relationships between their coloring mechanism and chemical composition. X-ray absorption near edge structure (XANES) analyses revealed that there are two mechanisms of red coloring in ancient Egyptian copper-red glass: a surface plasmon effect due to the presence of metallic copper nano-clusters, and the precipitation of reddish Cu2O crystals in the glass matrix. In the case of glass objects from the New Kingdom Period, the earliest stage of copper-red glass production in ancient times, only the crystalline-Cu2O was identified as being a coloring agent. In both coloring mechanisms, most of the copper contained within the copper-red glass exists as colorless Cu+ ion in the glass matrix. It was suggested that the coloring mechanism of copper-red glass changed from crystalline-Cu2O coloring to metallic-Cu nano-cluster coloring in ancient Egyptian glass production. Additionally, it was revealed that two kinds of copper-red glass were produced in ancient Egypt during the Ptolemaic/Roman Period by regulating the chemical state of Cu and the chemical composition of the flux of the glass.
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Intheframeworkofthe inter-disciplinary KongoKing project, a set of beads from archaeological excavations in the Democratic Republic of the Congo was analysed by means of a minimally invasive, multi-analytical approach based on micro-Raman spectroscopy. The full characterization of the materials, including glassy network, opacifiers and colorizers, was achieved thanks to the combination of data from handheld X-ray fluorescence, variable pressure scanning electron microscopy coupled with energy-dispersive X-ray spectrometry, micro-Fourier transform infrared spectroscopy and pyrolysis coupled to gas chromatography and mass spectrometry. The obtained chemical information was used to fill the existing gap in the chemical study of beads from Western Central Africa. The cobalt-rich blue beads were found to be of Central European origin, while the copper-rich turquoise beadsweremanufacturedusingdistinctcoppersources.Cadmiumyellowandcadmiumredarethecolourantsresponsible for thebrightcoloursofbeadtypes10and12,respectively.Thetype12beadswerefoundtobecomposedofglasscoveredwitha waxy layer tentatively identified as Japan wax. Prosser-moulded bead type 9 was coloured by means of a chrome–tin pigment, while a combination of Mn and Fe is responsible for the black colour of the type 47 beads. Cuprite is most likely responsible for the red hue of glass layers from type 14. The dark palm green exterior of the type 17 bead was produced by using a combination of Cu and Fe compounds; iron was the only chromophore detected in the Indian red decoration.
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Thousands of glass beads and beadmaking waste have been unearthed in the rescue excavation of Jiuxianglan (ca. 3rd century BC – 8th century AD), located on the alluvial fan of the Taimali Stream in southeastern Taiwan, since the end of 2003, suggesting that beadmaking may have been taken place in the early Iron Age in Taiwan. Forty-four glass artefacts from Jiuxianglan were analysed in this study, including beads and waste. The results indicate that there is not a complete match of the chemical composition and the microstructure between the finished beads and waste; therefore local production of beads analysed here is not supported by the evidence at this site and the finished glass beads may have been imported from the South China Sea region. Scientific analysis also revealed information on raw materials and the colouring process. While the red and orange glass beads are both coloured by cuprite, the source of the copper-containing raw materials appears to vary. The microstructure of orange and yellow glass beads from Jiuxianglan are also different from beads from other sites, suggesting different colouring raw materials or colouring processes. This information indicates that it was less likely that glass beads from Jiuxianglan were intensively re-exchanged to other sites.
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Glass material at early South Asian archaeological sites is mostly constituted of beads, bangles and otherpersonal ornaments; glass vessels are extremely rare and usually easily identifiable as imports from the West. Instead, glass–workers developed efficient techniques to produce large quantities of drawn glass beads. Several glass trade networks operated contemporaneously. After describing the origins of glass in South Asia, the dominant compositions encountered among the glass artefacts of this region are described and attention is devoted to the finds encountered at Arikamedu and related archaeological sites.
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A portable energy dispersive X‐ray fluorescence spectrometer and a micro‐Raman spectrometer are used for the nondestructive analysis of a batch of glazed pottery ornaments unearthed from Warring States Chu (楚) tombs (B.C.475–B.C.221) in Jiangling, Hubei Province, China. According to the chemical compositions obtained, all of the glazes belong to the lead–barium–silicate (PbO–BaO–SiO2) system and contain certain levels of copper. The man‐made barium copper silicate pigment crystals, such as Chinese blue (BaCuSi4O10) and Chinese purple (BaCuSi2O6), are identified from several samples by micro‐Raman spectrometer. Besides, gypsum and hematite are found in the white and brown regions of two eye beads. Combined with other glazed pottery and the related silicate artifacts (e.g., lead–barium glass and faience, potash–lime glass and glazed pottery, high‐lead glazed pottery, etc.), the origin, development, and affected factors of ancient Chinese low‐fired glazed pottery have been discussed preliminarily. The present study provides principal evidences for the technological provenance, raw material recipes, and the relationship between low‐fired glazed pottery and related vitreous materials of ancient China. It also provides some significant clues for the origin and the development of ancient Chinese lead–barium glass.
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In this work, Raman microspectroscopy and optical microscopy were for the first time used to examine pigments in Roman statues. The pigments were present in three statues found in the Torreparedones archaeological site, which is located in Baena (southern Spain). The statues represented a female, and the emperors Claudius and Augustus, all seated. The pigments comprised different hues and intensities of yellow, red and blue. As revealed by the Raman spectra, all yellow and red hues were from goethite (α-FeOOH) and hematite (α-Fe2O3), respectively. Some pigments additionally contained compounds such as calcium carbonate and sulphate, which were used in ancient times to enhance some colour hues, and calcium phosphate, a white pigment known as “bone white” and also used since ancient times but never previously found in mixtures with red. The blue pigment was invariably Egyptian blue and occasionally mixed with hematite to obtain purple hues.
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In this work, a simple and sensitive electrochemical aptasensor for protein (thrombin - TB used as the model) was developed by using cubic Cu2O nanocages (Cu2O-NCs) loaded with Au nanoparticles (AuNPs@Cu2O-NCs) as non-enzymatic electrocatalysts and robust redox probes. Through the specific sandwich-type reaction between TB and TB aptamers (TBA), the formed AuNPs@Cu2O-NCs bound with NH2-TBA were captured onto the electrode surface modified with SH-TBA. Based on the inherent redox activity of AuNPs@Cu2O-NCs with cubic nanostructures, a detectable electrochemical signal was generated which was dependent on the analyte concentration. Meanwhile, AuNPs@Cu2O-NCs showed an efficient electrocatalytic capability in the reduction of H2O2, resulting in a significant enhancement of the response signal. Thus, the simplification of the proposed strategy and the improvement of analytical performances were easily achieved with a sub-picomolar sensitivity (the limit of detection was 0.066 pmol L(-1)). The applicability of the simple and sensitive aptasensor was successfully demonstrated by assaying TB in human serum samples. This non-enzymatic detection platform would be potential and promising in clinical diagnostics and protein analysis techniques.
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The use of Raman spectroscopy for discriminating monetary emissions, a recurrent problem in much archaeological studies, is described. The method involves the record of Raman signatures of tenorite and crystalline and defective cuprite in the patina based on the idea that subtle, mint-characteristic variations in the composition and metallography of the base metal during the manufacturing process are reflected in the variation in depth of the composition and crystallinity of the corrosion patina. The technique was applied to a series of 10-cash copper coins produced around the transition between the Kuang Hsü and Hsüan T'ung last Chinese emperors and the first Republic whose averaged composition was 95 ± 1% wt Cu plus 5 ± 1% wt Zn often accompanied by traces of Sn and Pb. Raman data, corroborated by focusing ion beam-field emission scanning electron microscopy and voltammetry of immobilized particles measurements, suggested the possibility of discerning between different provincial and regular unified currency productions.
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Beads from graves of the Samad Culture. Sultanate of Oman, and from an ancient craftsmen quarter of the old kingdom of Ruhuna. excavated in Sri Lanka, were investigated using electron microprobe analysis and X-ray powder diffraction. Both experimental methods were optimized towards a non-destructive analysis of archaeo­ logical finds. Based on their analysis, the beads from Oman can be divided into those made from natural rocks or minerals, metal, glass, Egyptian Blue and synthetic enstatite. Preferred natural rock types are serpentinite, chloritite and massive chlorite amphibolite which occur in the Samail Ophiolite of Oman and indicate a local production of these beads. Garnet beads are almandine-pyrope-rich and are interpreted as imports from the Sri Lanka/India area. Metal beads are made from pure Ag. ± pure Au or from Ag-Au-Cu alloys. Reddish-brown glass beads from Oman are Na-rich and coloured by Cu present in the glass matrix. Opaque red glass beads from Sri Lanka are commonly K-rich and coloured by tiny cuprite droplets which recrystallized from the melt and which are intensively disseminated within the glass matrix. Blue-while-blue and brown-white-brown sandwich beads from Oman and Sri Lanka are stylistically similar, but differ in composition of the white glass. Parts of the glass beads from Oman is partially or completely altered to form smectite. A cogged wheel bead from Oman was cut from steatite and then hardened by transformation of the steatite lo synthetic enstatite during firing at about 1000'C. Large amounts of microbeads from a Samad grave also consist of synthetic enstatite and most probably were produced from Mg-rich clay by firing. Comparable beads have been recovered from excavations in the Indus area, especially Harappa. but also in the Arabian Emirates.
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An on-line database was compiled for the Raman and fluorescence spectra, obtained using three different excitation wavelengths (531.5, 632.8 and 780 nm), of 99 pigments analysed dry and already applied with four painting techniques (egg tempera, casein tempera, oil and fresco). The database makes it possible to determine easily the most suitable excitation wavelength for the identification of pigments already applied with these painting techniques. Copyright © 2004 John Wiley & Sons, Ltd.
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Mosaic tesserae, part of Roman villa floor decorations, from north-eastern Sicily and the Aeolian Islands, were analysed by means of micro-Raman spectroscopy and scanning electron microscopy–energy-dispersive x-ray techniques. Archaeologists considerate these ‘villa’ floor decorations (ranging from the 2nd century BC to the 4th century AD) as a stylistic product of North African workers or North African-style design that were imported from abroad. Much attention is paid in the technology of glass making in order to understand the capability of local workers to produce the same glassy material. Since the other coloured tesserae are definitively recognized as polished limestones and/or calcscists of well-known Sicilian geological formations, the glassy materials could be hypothetically interpreted in the same way. Spectroscopic and mineralogical techniques were applied to the materials in order to define both the colouring and opaquening agents. Bindheimite (Pb2Sb2O7), well known in past as ‘antique yellow’, was always found in both green and yellow glass tesserae, acting either as a colouring and/or an opacifier agent. Investigations were made in order to consider the possibility of local manufacturing techniques on the basis of widespread easy-to-find complex sulfide ore deposits in the area. Copyright © 2004 John Wiley & Sons, Ltd.
Article
The effects of heat treatment temperature and time on the rates of nucleation and growth, morphology, and colour of cuprous oxide crystals developed in a copper lead alkali silicate glass were investigated. The nucleation process is essentially completed in a very short time after heat treatment. The isothermal growth of the cuprous oxide crystals proceeds by diffusion-controlled and coarsening mechanisms in the early stage of crystallisation and by the coarsening mechanism alone in the later stage.
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Structural models, provided via Raman spectroscopy, which may be extrapolated to silicate liquids of geological relevance, are reviewed to facilitate access to the major experimental work in this field and to present recent results. The interpretations of the various experimental studies are discussed and the resulting models for silicate glass and melt structures are considered in order to identify points of general agreement and areas of current controversy where further studies are needed. The alkali and alkaline-earth silicate systems are best understood but the structural interpretations of aluminosilicate glasses and melts remain controversial as do the role of Fe3+, Ti and P in such melts.-R.A.H.
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Twelve gemstones set into the cover of an elaborately decorated leather-bound manuscript, the Tours Gospel, ‘Evangelia Quatuor’, held in the British Library (Add. MS. 11848), were identified by Raman microscopy to be composed of silica, amethyst, emerald (probable, 3), iron garnet (3) and sapphire (3), one not being identified. The brilliant illuminations within the manuscript (ca 825 AD) were established by Raman studies at 215 locations on 13 folios to have been painted with a restricted palette, which included carbon black, indigo, lead white, minium, orpiment and vermilion, together with certain mixtures of the above pigments. Gold was also used but, notably, not lazurite. The palette was compared with those found for the earlier Lindisfarne Gospels (ca 715 AD), part of a later Anglo-Saxon manuscript (ca 920 AD), a Paris Bible (1267 AD) and certain Gutenberg Bibles (1455 AD). Copyright © 2004 John Wiley & Sons, Ltd.
Article
An in situ, non-destructive study of the coloured glaze on ancient Egyptian faience objects has been performed. The research was undertaken to examine further the effectiveness of Raman microscopy as a tool for archaeometric analysis. Initial studies revealed that faience pigmentation could not be analysed when beneath the glaze but only through cross-sections where the glaze was broken or chipped. Further studies showed that Raman microscopy was unsuitable for the analysis of green, blue and white faience but was extremely effective for the analysis of red and yellow faience. A study of eight red and eight yellow faience fragments, dated to the XVIIIth Dynasty and uncovered at El-Amarna, revealed that all the red fragments were coloured with red ochre or red earth [iron(III) oxide plus clay and silica] and that the colour of the yellow fragments was due to lead antimonate yellow [lead(II) antimonate]. © 1997 by John Wiley & Sons, Ltd.
Article
Lead tin yellow type I (Pb2SnO4) and type II (PbSn1–xSixO3) have each been prepared in a high-temperature furnace, and the preparative conditions defined. The crystal structure of type II has been refined from powder X-ray diffraction data and indicates that the Sn and Si atoms are randomly distributed over the same type of site with Sn/Si ratio ≈ 3/1 (i.e., x≈¼). The Raman spectra of each form and also that of lead antimonate yellow (Pb2Sb2O7) have been obtained. Raman microscopy is shown to be an effective technique whereby these inorganic yellow pigments as minute (≈ 1 µm) grains may be identified on medieval manuscripts and paintings.
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A number of glasses were prepared using solar furnace melting and fast quench techniques. Samples with bulk compositions within the two-liquid field of the liquidus phase diagram were prepared at different quench rates. The Raman spectra give insight into the nature of unmixing and lead to a discussion of the role of metal cations in determining the structures.
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The Raman scattering intensity of the 1100 cm−1 polarized band, which appears on the addition of Na2O to SiO2 glass, reaches a maximum at the disilicate composition. The intensity of the polarized band at 950 cm−1 increases sharply as the Na2O concentration increases above 30 mole %. These data were interpreted by normal mode calculations and by IR and Raman intensity calculations for the silicate anion structural units: SiO4 isolated tetrahedra, Si2O7 dimers, Si2O6 chain links, Si2O5 sheet units, and Si2O4 framework units. According to these simplified models, the polarized high frequency band is due to symmetric stretching of Si–O− nonbridging bonds and the frequency increases with degree of polymerization of the tetrahedra. The previous assignments of the 1100 cm−1 band to the symmetric stretch of tetrahedra containing one nonbridging oxygen and of the 950 cm−1 band to the symmetric stretch of tetrahedra containing two nonbridging oxygens were confirmed. The other main feature of the alkali silicate glasses, an intense polarized band in the range of 400–600 cm−1, was shown to be a mixed stretching bending mode of the Si–O–Si bridging bond. The model also accounts for the loss of intensity of the high frequency band with increasing degree of silica polymerization.
Article
A Merovingian crucible fragment, with internally adhering yellow glass, and yellow glass beads of the same region and period were investigated by non-destructive XRF, optical microscopy and SEM-EDS. Although the microstructure and chemical composition of the yellow pigment (lead–tin yellow type II, ‘PbSnO3’) are almost identical in both the beads and the crucible, in the latter the pigment occurs in a much higher concentration. However, the glass base in the beads and the crucible is very different, indicating that the beads were not manufactured directly from the crucible. Instead, the crucible most likely served to produce lead–tin yellow, which was subsequently mixed elsewhere with a colourless soda–lime glass to produce yellow glass beads.
Article
Beads, rings and mosaic tessarae from Tunisia (Carthage and Utica, 1st centuries BC and AD, El Djem, 2nd–3rd centuries and Mahdia, 10th century) were analysed by Raman spectroscopy for non-destructive differentiation of various types of glasses (most have Si- and Na/Ca-rich compositions, some others are lead-containing glass) and identification of synthetic or natural minerals (crystal or stone). The results are discussed in the light of chemical analyses. A green glass is coloured by a Cr-based nanosized pigment and a red mosaic tesserae is obtained by a colloidal dispersion of gold (Cassius purple). Cassiterite (SnO2) is used as an opacifier or fluxing agent. The examination of glass mosaic and jewellery microstructure shows that some pieces are made of sintered glass, i.e. using a paste technology. Copyright © 2003 John Wiley & Sons, Ltd.
Article
We demonstrate the utility of Raman spectroscopy as a technique for the identification of ancient glasses and enamel coatings of ceramics. As for any silicate glasses, the addition of network modifiers breaks the Si–O linkages and modifies the degree of polymerization and hence the relative intensity of the Si–O bending and stretching modes. We demonstrate empirically that the ratio of these envelopes is well correlated to the glass structure and to the firing technology used. Spectral Qn components assigned to isolated and connected SiO4 vibrational units allow more precise analysis. Selected porcelains, faiences, potteries and glasses representative of the different Asian, Islamic and European production technologies were studied. Modern porcelain enamels are used as compositional references.
Article
To assist in the greatly increasing number of applications of Raman microscopy as a tool for non-intrusive, in situ archaeometric analysis, the Raman spectra of over 60 pigments, both natural and synthetic, known to have been in use before approximately 1850 AD, have been studied by Raman microscopy. Fifty-six pigments have yielded high quality spectra which have been arranged, by colour, into a spectroscopic library for reference purposes. The spectroscopic files may be downloaded from http:/(/)www.ucl.ac.uk/chem/resources/raman/speclib .html.
Article
Small catalogues of reference Raman spectra of interest for analysing geomaterials or biomaterials of relevance to art history or archaeology are gradually being published by different research groups. However, except for some older catalogues, they are all concerned primarily with pigments, whether inorganic or organic. Here we present for the first time a catalogue of Raman spectra of minerals that may be found in corroded metal artworks or artefacts. At the same time we include some inorganic pigments that may be found in or on stained glass. Most of the minerals analysed came from the Gallery of Mineralogy at the Muséum National d'Histoire Naturelle and most were verified by X-ray diffraction in order to augment the confidence in the mineral identity (which is not the case with many other catalogues). A number of problems encountered with mineral terminology are discussed. Comments are made on the spectra where appropriate.
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