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A set of decorative contemporary tile panels, created by the Portuguese artist Maria Keil (1914–2012) for the Lisbon metro stations, was studied under a noninvasive analytical methodology. This methodology combines X‐ray fluorescence spectrometry (μ‐XRF) and Raman spectroscopy in microscopic (μ‐Raman) mode for an elemental and structural composition characterisation of the glaze (glass matrix and network modifiers such as fluxes, opacifiers and colouring agents). μ‐XRF quantitative evaluation of the glassy matrix shows that all glazes have a lead silicate glass base. Results obtained by the combined use of μ‐XRF and μ‐Raman show that a zirconium‐based opacifier was used. Naples yellow (Pb2Sb2O7), lead–tin yellow type II (Pb(Sn,Si)O3), Pb–Sn–Sb triple oxide, cobalt blue (CoAl2O4), chromium oxide (Cr2O3) and malayite sphene (CaO·SnO2·SiO2) have been identified by μ‐Raman as some of the colouring agents, either used by themselves or in mixtures for obtaining the desirable colours intended by the artist. [ABSTRACT FROM AUTHOR]

This paper is a preliminary study on the origin of the precious red pigment cinnabar by μ‐Raman analysis. The importance of this pigment is partly due to its low availability. When the mineral was used in the Roman Age, the district of Almadén, Spain, was probably the most exploited region. However, it is still not well defined if further ores were chosen for supply. A scientific methodology has to be assessed. In the present study, samples with known provenance (Spain, Slovenia, Italy, Russia, China, and minor European deposits) were collected from Italian Mineralogical and Earth Science Museums. μ‐Raman analysis was chosen to acquire structural data, which were finally treated by statistical analysis. Most of the samples from China were characterized by the presence of selenium. This was proved by the additional band at ~200 cm−1. The statistical analysis of Raman data suggests that the position of the most intense band at ~252 cm−1 also influences the discrimination of the Chinese samples. This work also demonstrates that a higher purity may be revealed by μ‐Raman analysis, eventually leading to the discrimination of natural sources from synthetic cinnabar. It also proves that the most common exploitation sites, Almadén and Idrija, may be statistically distinguished. Despite its exploratory nature, this study is intended as a successful preliminary step to gain information of provenance from a single, potentially non‐destructive technique, such as μ‐Raman spectroscopy. [ABSTRACT FROM AUTHOR]

The purpose of this in vitro study was to assess whether the mineralization degree and elemental content in tooth enamel are altered when bleaching the teeth with two different over-the-counter bleaching gels, exceeding the recommendations of the manufacturer. In order to perform this evaluation, 12 healthy teeth were used, six samples were treated with Teeth Whitening Home Kit, and the other six samples were treated with WHITE! (Bingo-UK) bought in online shopping sites, for the period of 39 days. The pH of each product and the elemental content of each sample, before and after, were obtained by energy dispersive X-ray spectrometry and phosphate (PO43-) profile was evaluated with Raman spectroscopy. Data was analyzed accordingly to a pre-established plan with a mixed-model ANOVA for repeated measures, significance was set at 5%. Both products were markedly acidic and below enamel critical level of 5.5. Moreover, seven days after treatment, demineralization was significant, wherein at the end of the study the degree of demineralization seems to be permanent. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The first archaeological evidence reported for tile production in Portugal was discovered in Santo António da Charneca (SAC), late 15th or early 16th centuries' pottery kiln, south riverside of Tagus River. Samples from this kiln were studied with the use of non-invasive spectroscopies, namely, μ-Raman, ground-state diffuse reflectance absorption, Fourier transform infrared and particle-induced X-ray or X-ray fluorescence emission. These results were compared with the ones obtained for coeval tiles produced in Seville, Spain, originated from Portuguese archaeological sites, because it is well know that the Portuguese King Manuel the First imported in 1498 significant quantities of those tiles to decorate several palaces. The obtained results provided new spectroscopic insights, used to establish similarities but also clear differences regarding the SAC and the coeval Seville tiles found in Portugal. White glaze from both tiles gave evidence about the use of tin oxide as whitening agent and lead oxide as glassy agent. Cobalt oxides were also used as blue pigments in the two production centres. The brown and amber pigments in the samples from SAC derive from the manganese oxides dispersed in the lead-tin glaze, and kentrolite crystals were identified by μ-Raman in these tiles. In the arista and cuerda-seca tiles from Seville, diopside was detected. Divalent copper also exists in the green glaze matrix but in small amounts, which did not allow the Raman detection of the copper compound's microcrystals. However, diffuse reflectance measurements point to malachite green as responsible of green coloration. The Seville pastes contain calcium carbonate, although the SAC pastes do not evidence significant amounts of that compound in its composition. All the SAC pastes evidenced a high silica level, and quartz and anatase were clearly detected in the paste and possibly kaolinite. The Raman signals of orthoclase and calcium carbonate were detected in the Seville tiles. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]