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The Mars 2020 Perseverance rover has examined and sampled sulfate‐rich clastic rocks from the Hogwallow Flats member at Hawksbill Gap and the Yori Pass member at Cape Nukshak. Both strata are located on the Jezero crater western fan front, are lithologically and stratigraphically similar, and have been assigned to the Shenandoah formation. In situ analyses demonstrate that these are fine‐grained sandstones composed of phyllosilicates, hematite, Ca‐sulfates, Fe‐Mg‐sulfates, ferric sulfates, and possibly chloride salts. Sulfate minerals are found both as depositional grains and diagenetic features, including intergranular cement and vein‐ and vug‐cements. Here, we describe the possibility of various sulfate phases to preserve potential biosignatures and the record of paleoenvironmental conditions in fluid and solid inclusions, based on findings from analog sulfate‐rich rocks on Earth. The samples collected from these outcrops, Hazeltop and Bearwallow from Hogwallow Flats, and Kukaklek from Yori Pass, should be examined for such potential biosignatures and environmental indicators upon return to Earth. Plain Language Summary: Images and compositional data of Mars rocks taken by the Mars 2020 Perseverance Rover at Hogwallow Flats and Yori Pass in Jezero crater show an abundance of sulfate minerals. The goal of this study was to describe the characteristics of these rocks with close‐up views of places where these rocks were abraded to expose fresh rock surface, and to make preliminary interpretations of any preservation potential of any possible environmental and biosignature data. We found sand and silt grains with a variety of colors, some of which are sulfate minerals. We also found sulfate mineral crystals between and cross‐cutting the grains. The sulfate sand and silt grains may have originally grown as chemical sediments in past salty lakes, and the sulfate crystals found between and cross‐cutting the grains formed from past salty groundwater. Sulfate mineral grains and crystals on Earth contain fluid and solid inclusions, which are remnant water, air and other gases, other minerals, and microorganisms and organic compounds. From this knowledge of terrestrial sulfate minerals, we suggest that samples of Hogwallow Flats and Yori Pass, if returned to Earth, should be investigated for fluid and solid inclusions to be evaluated for any enclosed past Martian water, gas, minerals, and possible biosignatures. Key Points: We describe sub‐mm scale observations for abrasion patches Berry Hollow and Uganik Island at Hogwallow Flats and Yori Pass on the western fan front in Jezero craterThese are sulfate‐rich clastic rocks with various diagenetic features that suggest sulfate‐rich surface waters and groundwaterEnvironmental data, such as parent water temperatures and compositions, and any potential biosignatures, may have been preserved [ABSTRACT FROM AUTHOR]

Marble is one of the materials most susceptible to copper leaching, resulting in easily identifiable turquoise stains on the marble. This problem is particularly relevant when we are talking about marble structures of heritage value. For this reason, conservators look for cleaning materials that are specific to the structure to be treated without damaging the original surface. Materials such as agar have been studied for a long time. Agar creates a controlled water release system that adapts to the needs of conservators who seek the greatest possible cleanliness without damaging the material to be treated. To improve the cleaning, chelating agents such as EDTA are added to the agar composition. However, the microbiological growth and the damage it produces to the original material are disadvantages to take into account. In order to solve these problems, other natural materials with cleaning potential such as kudzu and konjac gels were studied in combination with other chelating agents such as citrate, oxalate, and gluconic acid. For the characterization and evaluation of copper cleaning, various analytical techniques were used, including Raman spectroscopy, colorimetry, X-ray fluorescence (XRF), and inductively coupled plasma mass spectrometry (ICP-MS). In this study, both konjac and kudzu emerged as promising alternatives to agar, revealing distinctive features such as simplified preparation methods and inherent antimicrobial properties. The EDTA chelator was found to be the most harmful for marble surfaces, as it extracted a greater amount of calcium from the marble during application of the gels doped with it. Citrate and gluconic acid have been identified as a promising substitute to prepare doped gels for the removal of copper stains. These compounds exhibit comparable or potentially superior cleaning capabilities than EDTA, with no negative side effects. [ABSTRACT FROM AUTHOR]

A fragment of the NWA 2975 Martian meteorite, an enriched basaltic shergottite, was analysed to complete its geochemical characterisation performed 10 years ago. By this means, the feasibility of the employed techniques in a combined way for present and future space exploration missions can be tested. For this aim, Raman spectroscopy was used supported by micro energy dispersive X‐ray fluorescence (μ‐EDXRF) and laser‐induced breakdown spectroscopy (LIBS) for an accurate interpretation of molecular and elemental results. Raman spectroscopy results from two setups, InVia from Renishaw and RLS Simulator, were compared. The major minerals detected by Raman spectroscopy were pyroxenes (mainly augite, pigeonite and enstatite) and plagioclases (mainly shocked maskelynite). Raman spectroscopy allowed defining different metal compositions for these main minerals based on the secondary Raman spectroscopy bands in the 200–500 cm−1 region. In addition, other minerals were found such as merrillite, as well as pyrrhotite and apatite, in several veins and cracks of the meteorite, in agreement with the initial report by the Meteoritical Bulletin. Moreover, it should be highlighted that coesite was found for the very first time in this meteorite. [ABSTRACT FROM AUTHOR]

In this work, the geochemical characterization of the olivine‐phyric Martian shergottite LAR 12095 was performed by using two complementary analytical techniques: micro‐Raman and micro‐energy dispersive X‐ray fluorescence spectroscopies. Thanks to this methodology, olivine, pyroxene, and ilmenite were detected as primary minerals from Mars. Maskelynite, hematite, anatase, chromite, merrillite, oxidized mackinawite, pyrrhotite, elemental sulfur, marcasite, jarosite, epsomite, and gypsum were classified as secondary minerals. The major novelty of this work is that alterations under anaerobic and aerobic conditions of S‐bearing minerals can be appreciated. In this sense, primary sulfides were altered to secondary sulfides, elemental sulfur and sulfates under the oxygen‐free Martian atmosphere. However, in the Earth's oxidizing atmosphere, primary sulfides are weathered to iron oxides, such as hematite. In addition, it should be highlighted that the presence of ilmenite, mackinawite, elemental sulfur, and jarosite has been reported for the first time in this meteorite. [ABSTRACT FROM AUTHOR]

High-altitude Pyrenean lakes are ecosystems far from local pollution sources, and thus they are particularly sensitive to the atmospheric deposition of metals and metalloids. This study aims to quantify the effect of human activity in 18 lakes located in both side of the France–Spain frontier. Sediment cores were collected in summer 2013, sampled at a 1cm resolution and the concentration of 24 elements was measured by ICP-MS. Statistic and chemometric analysis of the results highlights the influence of the geographical position and lithogenic features of each lake basin on trapping pollutants. More than the 80% of the lakes showed values of enrichment factor (EF) above 2 for at least one of the elements investigated in at least one core interval, which corroborates the existence of historical anthropogenic inputs of elements in the studied area. The results demonstrate the natural origin of As and Ti in Pyrenees, together with the significant anthropogenic inputs of Cd, Pb, Sb and Sn from ancient times. The data set points mining activities as the main historical source of pollution and illustrate the large impact of the industrial revolution. The regional variability could reflect also differential long-range transport, followed by dry or wet deposition. [ABSTRACT FROM AUTHOR]

In this work, some micro-samples belonging to the open-air rock art site of Cueva de la Vieja (Alpera, Albacete, Spain) were analysed. These samples were collected after and before a desalination treatment was carried out, with the aim of removing a whitish layer of concretion that affected the painted panel. The diagnostic study was performed to study the conservation state of the panel, and to then confirm the effectiveness of the treatment. Micro energy dispersive X-ray fluorescence spectrometry, Raman spectroscopy, and X-ray diffraction were employed for the characterization of the degradation product as well as that of the mineral substrate and pigments. The micro-samples analysis demonstrated that the painted layer was settled on a dolomitic limestone with silicon aggregates and aluminosilicates as well as iron oxides. The whitish crust was composed by sulfate compounds such as gypsum (CaSO4·2H2O) with a minor amount of epsomite (MgSO4·7H2O). An extensive phenomenon of biological activity has been demonstrated since then in almost all of the samples that have been analysed, and the presence of calcium oxalates monohydrate (CaC2O4·H2O) and dehydrate (CaC2O4·2H2O) were found. The presence of both calcium oxalates probably favoured the conservation of the pictographs. In addition, some carotenoids pigments, scytonemin (C36H20N2O4), and astaxanthin (C40H52O4) were characterized both by Raman spectroscopy and by X-ray diffraction. Hematite was found as a pigment voluntarily used for the painting of the panels used in a mixture with hydroxyapatite and amorphous carbon. The results of the analyses of the samples taken after the cleaning treatment confirmed a substantial decrease in sulphate formation on the panel surface. [ABSTRACT FROM AUTHOR]

It is assumed that the unique wall mirrors found at the Archaeological Park of Pompeii (PAP) are made of obsidian. To contribute to the knowledge of those archaeological artefacts, this work proposes in situ elemental analyses in collaboration with PAP seeking to determine, in a total no-destructive way, the composition and provenance of the main mirror preserved at the House of Gilded Cupids. Comparing the geochemical composition of this black glass with that of obsidian samples collected from the main Mediterranean sources, both X-ray fluorescence (XRF) and laser-induced breakdown spectroscopy (LIBS) confirmed an incompatible content of many key elements. LIBS in-depth analysis excluded the potential relation between the higher concentration of Ca and Mg and the presence of alteration products. In addition, XRF analysis missed the detection of Rb, Y, Zr and Nb, which are widely recognized as the elemental fingerprints of obsidian sources. Combined with the detection of a high content of strontium (500–700 ppm), the in situ elemental data proved that, rather than made of obsidian, the analysed mirror was handcrafted by the fusion of coastal sand. Waiting to extend this study to the other mirrors found at Pompeii, the results here presented indicate the history of these unique artefacts needs to be rewritten. [ABSTRACT FROM AUTHOR]

This work presents a new calibration method for determining the provenance of obsidian artefacts based on the combined use of XRF and laser-induced breakdown spectroscopy (LIBS). At first, obsidian samples collected from the main Mediterranean sources were characterized using portable XRF and LIBS systems. After data treatment, elemental information was used to carry out principal component analysis (PCA) for each technique. Rb, Sr, Zr, Y and Fe elements, detected by using XRF, were found to be the key parameters enabling obsidians discrimination. Likewise, LIBS data helped differentiating the analysed patterns by the intensity of their main elemental components (Ca, Al, Mg and K). After selecting the key parameters detected by each technique, a new data matrix combining XRF and LIBS data was finally built. According to PCA results, the discrimination of Mediterranean sources based on combined XRF–LIBS data ensured a higher reliability over mono-analytical models, by increasing the Euclidean distance between sources projections over three-dimensional principal components plots. Knowing that the representativeness of elemental data could be compromised by the presence of superficial degradation products or deposition patinas, a shot-to-shot comparison of in-depth LIBS analyses is finally proposed as a method to disclose whether the spot under analysis was superficially contaminated or altered. Thus, the proposed strategy based on the combined use of portable XRF and LIBS spectrometers could be particularly useful for the in situ analysis of obsidian artefacts that underwent superficial alteration or could be covered by patina products. [ABSTRACT FROM AUTHOR]

The analysis of Martian meteorites is a key research to understand the mineralogical composition of Mars. However, they suffer different types of alteration due to the environment where they fall on Earth. These differences should be identified in order to characterize correctly the original Martian compounds. Most of the meteorites found on Earth are collected in Antarctica where the environmental conditions are such that, in general and based on many previous investigations, produce fewer alterations compared with other terrestrial environments such as hot deserts. In this study, the weathering alterations of minerals from the MIL 090030 Martian Nakhlite found in Antarctica were analyzed to determine which minerals are formed by Antarctic environmental conditions. It was confirmed that the south-polar region environment can contaminate Martian meteorites and, in this study, several minerals like halite, nitratine and niter, were detected as weathering alteration products that have not been referenced in the literature before. [ABSTRACT FROM AUTHOR]

Raman spectra (532 nm diode laser) of gypsum, syngenite and görgeyite powders were studied from 273 to 83 K every −10 K. Although it was found that not all the Raman peaks are temperature-sensitive, the effect of temperature on the Raman signal of some bands was modelled. It was observed that the main bands of the three sulfates shift toward higher wavenumbers as temperature decreases. The strengthening of the bonds causes an increase in energy and, consequently, higher wavenumbers. However, –OH bands shift depending on the crystal structure they acquire as the temperature decreases, so not all –OH bands behave in the same way. Finally, the gypsum –OH bands change to more ordered crystalline structures with decreasing temperature, so their bandwidths become narrower and sharper. [ABSTRACT FROM AUTHOR]

The presence of olivine and its geochemical composition (forsterite/fayalite ratio) are relevant factors for the study of Mars. The use of Raman spectrometers in the Mars 2020 and future missions opens new possibilities to assess the Mg/Fe ratios in the analyzed olivine bearing rocks. On the one hand, its presence indicates approximately where and when Mars had volcanic activity, due to the partial weathering of this mineral into other secondary minerals. On the other hand, the forsterite and fayalite content of olivine can be used to study the origin and evolution of its parent magma, since this mineral is one of the first to crystallize from it. In order to properly study the forsterite and fayalite ratio of olivines, this work proposes a new calibration model using Raman spectroscopy, doing a thorough literature review of previous studies in order to improve the calibration quality. The proposed model improves greatly the accuracy and uncertainty associated with the final result of forsterite and fayalite (around 2%) compared to those published earlier in the literature (around or above 10%). Using the new model, it will be possible to assess the forsterite and fayalite ratios of Martian olivines properly, providing relevant information about their parent magma. [ABSTRACT FROM AUTHOR]

The Mars Sample Return (MSR) is a near future mission to return samples from the surface of Mars to the Earth. The field operations to carry out data collection, selection of the samples, and sampling procedure, mainly related to the CanMars MSR analog mission, are well‐studied and published. In contrast, studies related to the methodology implemented to characterize the mineralogy of the returned samples are scarcer and focused on biosignature detection. This work presents a non‐destructive analytical methodology based on Raman microscopy (single point and imaging), micro‐energy dispersive X‐ray fluorescence imaging analysis, and scanning electron microscopy coupled to energy dispersive spectroscopy that could be used as a first analytical characterization for the Martian samples that will be returned to the Earth in the upcoming MSR mission, before any destructive analysis. The analytical methodology has been tested on a fragment of the Northwest Africa 1950 Martian meteorite, which gives us a mineralogical characterization of the meteorite. This methodology also allowed to define several chemical reactions taking place in some of the mineral phases (olivines and ilmenite) of the meteorite. In addition to the geochemical characterization of the samples, the fact that this methodology allows to assess the chemical transformations in several minerals gives important clues for describing mineral processes and geological evolution that took place on Mars. This work also shows the advantages and disadvantages that each of the techniques employed has when performing a mineralogical characterization, the information that each one can provide and the importance of combining them. [ABSTRACT FROM AUTHOR]

The blackening of red cinnabar (α-HgS) pigment has traditionally been explained by its conversion into black metacinnabar (β-HgS). Scarce is however the scientific evidence that supports this hypothesis in polychrome artworks. As such transition occurs at around 345 °C, the thermal impact of the eruption of Mount Vesuvius in 79 AD could have induced this structural change of the pigment present in the mural paintings of Pompeii. This work aims to assess whether the mentioned volcanic eruption could be responsible of the cinnabar blackening through the formation of metacinnabar. The thermodiffractometry study of cinnabar-decorated fresco mock-ups stated that the formed β-HgS is not stable, observing its reversion into α-HgS. Moreover, sublimation of the cinnabar pictorial layer was registered, also when the cinnabar paint layer was protected by a coating of pyroclastic materials. In real blackened cinnabar Pompeian samples, it was not possible to identify metacinnabar by X-ray diffraction (XRD), but evidence of sublimation of mercury due to the thermal impact was observed. Hence, this blackening seems to be related mainly to the presence of calomel (Hg2Cl2) and a gypsum (CaSO4·2H2O) crust as degradation products of red cinnabar and the calcite mortar, respectively, and not to the formation of metacinnabar. Finally, laser-based techniques could also induce modifications in the HgS crystalline structure, resulting in an amorphous black product. Therefore, the elemental and molecular study of the species promoted by laser impact was carried out to avoid false positives in the metacinnabar detection or when the decorated surface has been subjected to laser cleaning. [ABSTRACT FROM AUTHOR]

The toxicity and the health risk assessment associated to the presence of some hazardous elements (HEs) in dried (infant formula and powdered) milks due to manufacturing and packaging process, raw materials used, environmental conditions, etc. need to be determined. With this aim, a new methodology based on the combination of health risk quotients and non-supervised (as cluster analysis (CA) and principal component analysis (PCA)) chemometric techniques is proposed in this study. The methodology was exemplified using the concentration of 27 elements, some of them HEs, measured in 12 powdered milk samples produced for children and adults in Brazil and Colombia. The concentration values were obtained by inductively coupled plasma-mass spectrometry (ICP-MS) after acid microwave digestion. Elemental concentrations vary depending upon the type of milk (initiation, growing-up, follow-on milks and adult milks). However, hazard quotients (HQ) and carcinogenic risk (CR) values showed no risk associated to the presence of HEs on milks. The methodology designed made possible to conclude that adults' milks are more characteristic of elements naturally present in milk. Children milks present major presence of trace and minor elements. Between infant milks, sample H, designed for babies between 12 and 36 months, was identified as of poor quality. Moreover, it was possible to deduce that while the fortification process applied to children powdered milks is a probable metal and metalloid source, together with the manufacturing, the skimming process is not a contamination source for milks. [ABSTRACT FROM AUTHOR]

In this work, micro-Raman spectroscopy and micro-energy-dispersive X-ray fluorescence spectroscopy (µ-EDXRF) were applied on microsamples taken from the Plaiko Zubixe footbridge (1927) located in Ondarroa (Basque Country, Spain) in order to investigate the original paint coating and make an evaluation of the conservation state before its restoration. Elemental and molecular images were acquired for the study of the compounds distribution. Some modern pigments such as phthalocyanine blue and green pigments, minium, calcium carbonate, Prussian blue, and hematite were identified. Barium sulfate and titanium dioxide were recognized as opacifier agents. Thanks to the study of the stratigraphies, it has been possible to determine the original paint layer, which includes lead white, ultramarine blue, carbon black, and barium sulfate. In addition, colorimetric analyses made it possible to know the CIELab values of the original layer in order to reproduce the original colour during the planned restoration work. The massive presence of chlorine detected by µ-EDXRF and the corrosion products of the rust layer, in particular akaganeite and hematite, highlighted the atmospheric impact in the conservation of the bridge because they were due to the effect of both marine aerosol and to the presence of acidic components in the environment coming from anthropogenic activity. This work demonstrated the usefulness of a scientific approach for the study of industrial archaeology heritage with the aim to contribute to its conservation and restoration. [ABSTRACT FROM AUTHOR]

Martian meteorites and terrestrial analogs represent the only samples available on Earth for studying mineralogy features of our neighbor planet Mars. This work characterizes the Roberts Massif (RBT) 04262 Martian meteorite by using mainly Raman spectroscopy. By means of this technique, it was confirmed that the meteorite matrix is composed by pyroxene and plagioclase (converted to maskelynite due to the shock pressure). Olivine‐coarse grains embedded in the matrix were also observed. These grains were coated by hydrated magnesium and calcium sulfates, which would belong to the Mars sulfate deposits or to the terrestrial weathering. Although the sulfates could be formed on Mars due to the oxidation of sulfides or elemental sulfur along the sulfur Mars cycle, their distribution along cracks and fractures confirm that are weathering products. However, other S‐bearing compounds that belong to Mars were found, such as elemental sulfur and a thermally transformed iron sulfide. Finally, the calcium phosphate merrillite and titanomagnetite were also detected. Taking this into account, the minerals found were classified into primary minerals that belong to Mars (pyroxene, olivine, elemental sulfur, and titanomagnetite), secondary ones that are alteration products of the primary minerals (maskelynite, iron sulfide, and merrillite), and terrestrial weathering products (sulfates gypsum and epsomite). [ABSTRACT FROM AUTHOR]

Raman spectroscopy was applied for the diagnostic study of some commercial mortars applied to the outside of Punta Begoña Galleries, a historical building located in a coastal environment (Basque Country, Northern Spain) with industrial activities. Molecular analyses were carried out to study the conservation state of commercial materials exposed to the environmental stressors with the aim of being used for future restoration works of the Galleries and to assess in this way their stability when exposed to aggressive agents. The presence of the degradation compounds was studied considering the orientation of the walls where the commercial mortars were placed. Among the decay products, gypsum (CaSO4·2H2O) was identified in a higher number of samples together with sodium nitrate (nitratine, NaNO3) in a minor amount. The presence of magnesium‐based secondary products, nitromagnesite (Mg(NO3)2) and dypingite [Mg5(CO3)4(OH)2·5(H2O)], was also found formed by the degradation of original magnesium compounds of the mortars. Raman analyses showed in almost all the samples the presence of the xanthophyll carotenoid astaxanthin, which is considered as a bioindicator of pollution level because it appears as the first xanthophyll in highly contaminated areas. The presence of calcium oxalates whewellite (СаС2О4·Н2О) and wedellite (СаС2О4·2Н2О), formed probably as a result of secretion of microorganisms, was detected. However, these compounds were only identified in samples from the south‐west orientation, which is most affected by the influence of the harbour activity, indicating a higher anthropic impact in the materials in that area. Therefore, the choice of materials for restoration will have to be made considering the different environmental impacts. The obtained results were very useful to understand the deterioration processes on commercial mortars in order to study the atmospheric impact that these aggressive environments have on modern material in a relatively short period after their application. [ABSTRACT FROM AUTHOR]

NorthWest Africa 10628 (NWA 10628) is a shergottite found in Tindouf (Algeria) in 2014. Little is known on this meteorite apart from the Meteoritical Bulletin report. In this work, original and altered mineral phases of NWA 10628 were characterised by micro‐Raman spectroscopy assisted with micro‐energy dispersive X‐ray fluorescence imaging. The matrix of the meteorite is dominated by high‐Ca pyroxenes, augite ((Ca,Na)(Mg,Fe,Al,Ti)(Si,Al)2O6) and diopside (CaMgSi2O6). Olivine and feldspars appeared as small crystals all along the matrix. Merrillite (Ca9NaMg(PO4)7) was found as big crystals in inclusions. As whitlockite (Ca9NaMg(PO4)6(HPO4)) can be transformed into merrillite at high temperature and pressure, we suggest that merrillite in the meteorite was originally whitlockite, before its ejection from Mars. Gypsum (CaSO4·2H2O) was found as small crystals and in fractures; this last one could come from terrestrial weathering because it was associated with calcite (CaCO3). Small anhydrite (CaSO4) crystals are shown in the bulk together with gypsum, probably from the partial dehydration of original Martian gypsum by the high‐pressure/temperature of ejection. Pyrite and marcasite (FeS2 polymorphs) minerals were detected, as well as their oxidation products, goethite (α‐FeO (OH)) and rozenite (FeSO4·4H2O), due to their terrestrial weathering. The identification of hematite (Fe2O3), magnetite (Fe3O4), ilmenite (FeTiO3) and anatase (TiO2) suggested that ulvospinel (Fe2TiO4) was the precursor on Mars, because ulvospinel is transformed into ilmenite by pressure and later ilmenite can be altered to magnetite/hematite and anatase by oxidative weathering on Earth. This non‐destructive analytical methodology provides deep mineralogical characterisation adequate for scarce samples like those returning from the Mars Sample Return mission. [ABSTRACT FROM AUTHOR]

This work describes the characterization of green pigments in wall paintings from the Andean churches of San José de Soracachi and Santiago de Callapa in Bolivia, located on an ancient colonial commercial route known as the Silver Route. To approach our goal, microsamples extracted from the mural paintings and mineral samples, from a mine of the same area, were studied by using micro‐Raman spectroscopy complemented with micro‐energy‐dispersive X‐ray fluorescence spectroscopy (μ‐EDXRF) and scanning electron microscopy with energy‐dispersive X‐ray spectroscopy (SEM‐EDS) analysis. The use of gypsum as the preparation layer was detected, and it suggests a secco painting technique. Antlerite, a basic copper sulfate, was identified suggesting a preference for its use as green pigment in the mural paintings of Andean churches that may be related to the local availability of this mineral. Indeed, this study revealed the presence of heterogeneous particles of the basic copper sulfate together with aluminosilicates, quartz and iron oxides among others, which points to a mineral origin of the green pigment because the same compounds were found in the samples taken in the mine. Because a phase transition has been noticed during the Raman analyses, due to a high power of the laser radiation, some tests have been carried out, varying the laser power, and coupling the Raman spectrometer to a temperature‐controlled stage to verify under which conditions the degradation of the mineral sample of antlerite occurs allowing in this way a correct characterization of basic copper sulfate pigments. These results contribute to the study of the Andean colonial artistic cultural heritage, and this information will be made available for the construction of a database of local pigments of mineral origin used in Andean colonial art. [ABSTRACT FROM AUTHOR]

Although Raman spectroscopy is a common technique for the analysis of cement‐based materials in the research studies or in the field of Cultural Heritage to carried out multianalytical studies, it is not generally used as unique technique of a research or to carry out analysis during ordinary restoration works of modern urban buildings affected by environmental stressors. The disadvantages associated with Raman spectroscopy as fluorescence limits its implementation beyond research studies, more in the case of in situ equipment. However, the technological development allows high‐quality results with in situ equipment, so its use could be useful during restoration works. Thus, this work demonstrates how the implementation of the correct methodology could lead to useful and fast results during restoration works. The proposed methodology is based on the use of in situ analysis (screening) on the scaffolding, followed by the sampling of layers based on the previous screening and a posterior exhaustive laboratory analysis. The research has been conducted during the restoration works of a reinforced concrete building in which the attack of atmospheric acid gases (CO2, SO2, and NOx) was identified as the main affection suffered, and the fixed sulfates were the most important intermediary compounds of decaying processes. Many of the pollutants and decaying compounds were even identified during the in situ analysis, improving the anticipation and responsiveness. Therefore, this methodology allows the understanding of the chemistry of the materials to evaluate its health state in a fast and reliable way. [ABSTRACT FROM AUTHOR]

The Historical and Cultural Heritage of Punta Begoña Galleries in Getxo (Bizkaia, North of Spain) are currently in restoration after being abandoned for years. For that reason, many graffiti, which directly affect the wall paintings, appear on most of their walls. Moreover, several graffiti overlap each other, which makes their removal more difficult. For all these reasons, the chemical characterization of these pigments is a priority to optimize the cleaning and consolidation treatments of wall paintings. That being the case, an analysis based on Raman spectroscopy and X-ray fluorescence was carried out to obtain information to help conservators remove the graffiti without damaging the mural paintings and the support. Nevertheless, the first step, using X-ray fluorescence and Raman spectroscopy, involved the need for a database to compare the results and identify the compounds. Thus, different commercial inks were elementally and molecularly characterized to complete the existing databases. After this, an analysis of the inks was carried out that noted the presence of several organic pigments, such as phthalocyanines. Inorganic pigments such as titanium oxide were identified as well. After the analysis, the selection of the best removal process could be carried out to provide the most effective treatment, avoiding the "trial-and-error" classical practice. [ABSTRACT FROM AUTHOR]

The conservation of iron objects exposed to marine aerosol is threatened by the formation of akaganeite, a highly unstable Cl-bearing corrosion phase. As akaganeite formation is responsible of the exfoliation of the rust layer, chlorides trigger a cyclic alteration phenomenon that often ends with the total consumption of the iron core. To prevent this degradation process, movable iron elements (e.g. archaeometallurgical artefacts) are generally immersed in alkaline dechlorination baths. Aiming to transfer this successful method to the treatment of immovable iron objects, we propose the in-situ application of alkaline solutions through the use of highly absorbent wraps. As first step of this novel research line, the present work defines the best desalination solution to be used and optimizes its extraction yield. After literature review, a screening experimental design was performed to understand the single and synergic effects of common additives used for NaOH baths. Once the most effective variables were selected, an optimization design was carried out to determine the optimal conditions to be set during treatment. According to the experimental work here presented, the use of 0.7 M NaOH solutions applied at high temperatures (above 50 °C) is recommended. Indeed, these conditions enhance chloride extraction and iron leaching inhibition, while promoting corrosion stabilization. [ABSTRACT FROM AUTHOR]

Pyroclastic strata have always been thought to protect the archaeological remains of the Vesuvian area (Italy), hence allowing their conservation throughout the centuries. In this work, we demonstrate that they constitute a potential threat for the conservation state of the mural paintings of Pompeii. The ions that could be leached from them and the ion‐rich groundwater coming from the volcanic soil/rocks may contribute to salt crystallisation. Thermodynamic modelling not only allowed to predict which salts can precipitate from such leaching events but also assisted the identification of additional sources of sulfates and alkali metals to explain the formation of the sulfates identified in efflorescences from the mural paintings of Pompeii. For the future, fluorine, mainly related to a volcanic origin, can be proposed as a marker to monitor the extent of the impact in the mural paintings of Pompeii in situ. [ABSTRACT FROM AUTHOR]

Pyroclastic strata have always been thought to protect the archaeological remains of the Vesuvian area (Italy), hence allowing their conservation throughout the centuries. In this work, we demonstrate that they constitute a potential threat for the conservation state of the mural paintings of Pompeii. The ions that could be leached from them and the ion‐rich groundwater coming from the volcanic soil/rocks may contribute to salt crystallisation. Thermodynamic modelling not only allowed to predict which salts can precipitate from such leaching events but also assisted the identification of additional sources of sulfates and alkali metals to explain the formation of the sulfates identified in efflorescences from the mural paintings of Pompeii. For the future, fluorine, mainly related to a volcanic origin, can be proposed as a marker to monitor the extent of the impact in the mural paintings of Pompeii in situ. [ABSTRACT FROM AUTHOR]

The 10th edition of the International Congress on the Application of Raman Spectroscopy in Art and Archaeology (RAA2019) was held in Potsdam (Germany) from 3 to 7 September 2019, with eight keynote lectures, 35 oral presentations and 18 Poster Presentations. RAMAN SPECTROSCOPY OF ORGANIC-BASED MATERIALS Confocal -Raman spectroscopy, equipped with an excitation laser at 785 nm, was used by Rigula et al. SP [ sp 20 SP ] sp to perform a depth-profiling study of an 18th century gun-powder horn. The pigments employed on these samples were identified by Raman spectroscopy, finding lead oxides, calcium antimonate, haematite and Naples yellow as the typical ones used in more than 400 years. -Raman spectroscopy analysis of a set of Southern Italy pottery materials, dated between 13th and 16th century, was performed by Caggiani et al. SP [ sp 25 SP ] sp A total of 27 samples taken from six archaeological sites of Campania and Sicily were studied non-invasively to obtain information on the nature of glass surface, the opacifying minerals and the pigments used to obtain the different colours. [Extracted from the article]

Ariadne's house is in the Regio VII of the Archaeological Park of Pompeii (Italy). As it is exposed to external alteration agents (rainfall, water infiltration and atmospheric pollution), the mural paintings located in this important residence clearly show the effects of ongoing degradation processes. This is especially the case of Room 22 (also called the blue room), where the original blue decorations varied towards greyish green hues. In situ and laboratory spectroscopic analyses by means of non‐destructive X‐ray fluorescence, infrared and Raman spectroscopies identified the original pigments and the materials used in the conservation works. Looking in detail at the stratigraphic distribution of the original pigments, using Raman spectroscopy, an inner layer of Egyptian blue mixed with celadonite was detected under a layer of pure Egyptian blue. This discovery proves the presence of a more ancient painting below the one that can be observed today. Considering that celadonite was an inexpensive pigment (thus, probably used to reduce the costs of the paintings), this information strengthens the hypothesis that based on archaeological evidences, there is evidence of an evolution of the socio‐economic status of the ancient owners of the residence. In addition to that, Raman data also proved the occurrence of salt efflorescences; they provided insights about the compromised conservation state of the wall paintings, and they highlighted the action of atmospheric acid gases as an important factor. [ABSTRACT FROM AUTHOR]

The use of portable Raman is proposed as the modern hammer of architects to inspect protected buildings of the 20th century, where reinforced concrete was used for structures and Portland type cement for mortars/binders in the walls. Two different buildings in the province of Biscay (North of Spain) were selected, the Punta Begoña Galleries, Getxo (1918), qualified as monument, affected by a direct marine and hard industrial environment from the Bilbao Commercial Harbor, the Library of the University of the Basque Country UPV/EHU, Campus of Leioa (1968), affected by the diffuse urban‐industrial atmosphere of metropolitan Bilbao. For both cases, original and decayed compounds were searched by portable Raman spectroscopy (785‐ and 532‐nm lasers) in raw materials and efflorescence salts over them. In the Galleries, the expected raw materials of Portland‐type mortars and reinforced concrete were detected, such as alite (3CaO·SiO2), belite (2CaO·SiO2), calcite (mortar and gravel) and gypsum together with quartz and aragonite, which indicates the use of beach sand as aggregate. Other compounds like nitratine (NaNO3), nitrocalcite/niter (Ca (NO3)2.6H2O/KNO3), γ‐anhidrite (CaSO4), bassanite (CaSO4·1/2H2O), mackinawite ((Fe,Ni)S), lepidocrocite (γ‐FeO (OH)), haematite (Fe2O3) and whewellite (CaC2O4·H2O) indicated also a heavy decay, because of chemical reactions between compounds in the aerosols around the building and original materials. In the Library of the UPV/EHU, apart from the same kind of original compounds, high amounts of niter (KNO3) were detected in efflorescence just underneath the upper gardens of the building, suggesting a decay due to the infiltration of ammonium nitrate charged waters. Moreover, thenardite (Na2SO4), syngenite (K2Ca(SO4)2·H2O), gypsum (in efflorescence salts), aphthitalite (K3Na(SO4)2), haematite and anatase (TiO2) were also detected in other efflorescences. [ABSTRACT FROM AUTHOR]

Cultural heritage often brings to mind elements like sculptures, paintings, monuments, and buildings as well as archeological objects. Today, underwater heritage and its surrounding environment are also considered part of cultural heritage because communities identify themselves with the natural landscape. This study is focused on a shipwreck belonging to the second half of the 15th century that was discovered in 1998 by chance in the sediments of the Urdaibai estuary, in Urbieta (Gernika, Basque Country), at 4 m underground. A scientific study presented in this work was performed, as this archeological site was absolutely out of context and in need of a preservation and conservation procedure. Therefore, our aim was to shed light on the origin of the shipwreck and to assess the conservation state to develop a precise conservation plan. Pursuing this objective, a first analysis on three selected groups of iron nails was performed, looking at the raw materials and degradation patterns through the knowledge of the alteration compounds. By means of nondestructive analytical techniques such as Raman spectroscopy and X‐ray fluorescence, the presence of iron, zinc, and silicon was detected in the outer layer of the iron samples. The analysis of the nails and wood of the shipwreck confirmed that the presence of zinc in the pieces indicates an important impact of the contaminated sediments deposited in the last 80 years on the upper part of the burial in which the shipwreck was located. [ABSTRACT FROM AUTHOR]

In this work, an innovative non-destructive monitoring methodology based on the analysis over time of open-air rock art sites is presented. This approach is based on the combination of in situ spectroscopic and chemometric studies to diagnose and monitor the state of conservation of rock art sites. Data acquired over a period of time by non-invasive analytical techniques such as portable Raman spectrometry (RS) and handheld energy-dispersive X-ray fluorescence (HH-EDXRF) spectrometry are compared to detect physicochemical changes that could affect the rock painting integrity. To demonstrate the applicability of the proposed procedure, three analysis campaigns (between 2013 and 2016) were carried out, analyzing Levantine rock pictographs preserved in the rock shelter of Solana de las Covachas VI (Albacete, Spain; see Electronic Supplementary Material (ESM) Fig. S1). The analyzed areas showed different types of active weathering processes such as gypsum and calcium oxalate formation, giving rise to conservation issues such as painting fading, surface loss, microbial colonizations, and formation of crusts. Results evidence that the proposed methodology can be very useful to monitor chemical changes in the surface of the walls where the rock art is located, thus obtaining crucial information for its preservation and management. [ABSTRACT FROM AUTHOR]

Hazardous elements are usually incorporated in natural fresh waters forming inorganic compounds or adsorbed onto organic matter as insoluble compounds in suspended particulate matters (SPMs). Considering the predominant transport of SPMs during heavy rainfalls, storms, or snow melting, such events require deep and exhaustive research to evaluate their environmental risk. The present work applies Raman spectroscopy for the analysis of SPM samples collected during a storm event (collected every 2 hr with an automatic water sampler) in a gauging station of an urban river (Deba River, one of the most polluted rivers in the Basque Country, Spain). In order to obtain revealing molecular information about the hazardous element distribution on the SPM during strong rainfall events micro‐Raman spectroscopy and Raman imaging were combined. The molecular characterization by Raman analysis determined that the main part of the compounds was from natural origin, such as, quartz, silicates, talc, calcite, etc. Contrary to oxides or oxi/hydroxides of lead, zinc, iron, titanium, or manganese, which were, probably, from anthropogenic origin. Those results were in agreement with energy‐dispersive X‐ray fluorescence and X‐ray diffraction analyses on SPM samples. Organic compounds such as calcium oxalate, amorphous carbon and β‐Carotene, and carbonates, such as, calcite, high‐Mg calcite, dolomite, strontianite, and graphite, as crystalline allotrope of carbon, were also found. Finally, Raman imaging analyses provided evidence enough to conclude that in the flood event studied, the SPMs firstly mobilized were rich in compounds with anthropogenic and/or natural origin, and the SPMs mobilized in the second part of the event were characterized by natural compounds coming from the lithogenic components of the area. Therefore, these discoveries support Raman imaging as a useful technique on the future sustainable management framework of the river. [ABSTRACT FROM AUTHOR]

The European Space Agency will launch the ExoMars Martian mission in 2020, which will study traces of water activity through the geological history of Mars, as water would mean potential presence of life. In this sense, silicates, and more concretely phyllosilicates, are among the most relevant mineral phases to be studied on the Martian surface at Oxia Planum, the selected landing site. Phyllosilicates are widely spread over the planet, together with sulfates and carbonates, in places where liquid water seems to have been present, and, therefore, knowledge about their mineralogy is of high importance. Thus, the creation of Raman and visible near‐infrared (VNIR) mineralogical databases can be critical for the interpretation of both the terrestrial analogues and the upcoming data from Mars, as Raman and VNIR spectroscopies will be on board the rovers of the ExoMars as well as of the NASA Mars 2020 missions to Mars. For that purpose, several phyllosilicates of the collection of the Geominery Museum of the Spanish Geological and Miner Institute were characterized geochemically to be used as reference. A wide number Raman and VNIR spectra of common and rare phyllosilicates were collected, and several of these are presented here. [ABSTRACT FROM AUTHOR]

The necessity to create databases for the proper interpretation of the results obtained by the rovers that will be sent by ESA to Mars implies the study of terrestrial Martian analogues. In this work, the Meñakoz outcrops, which are basaltic volcanic rocks interbedded with Turonian sediments coming from a Cretaceous submarine volcano outcrop located in Biscay (northern Spain), have been studied and proposed as a Martian analogue. Considering that Raman and near infrared spectroscopies are two of the techniques that will go on‐board the rovers in the next planetary missions, they were used to characterize the samples collected in Meñakoz. As was expected, silicates (phyllosilicates) were the major minerals detected by those techniques in the Meñakoz samples, but also, compounds such as sulfates and oxides could be detected. Phyllosilicates are very important because they are some of the compounds that have been reported to be present on the Mars surface in previous missions and specifically in Oxia Planum, the landing site for the ExoMars 2020 rover of the ESA missions to Mars. This fact provides reasons to propose the emplacement of Meñakoz as Martian analogue. [ABSTRACT FROM AUTHOR]

This work reports the results of an extensive study carried out on the wall paintings preserved inside the Saint Stephen's chapel in Montani (Val Venosta, Bozen, Italy), by means of μ‐Raman spectroscopy, portable X‐ray fluorescence (XRF) spectrometry, and powder X‐ray diffraction, in order to characterize materials and their alteration products that cause the blackening of paintings. In situ XRF analysis allowed identifying the areas of interest where the blackening appeared. The complementary analytical techniques allowed reconstructing a chromatic palette used by the artists that includes expensive pigments, such as lapis lazuli and cinnabar, indicating a wealthy client. Raman spectra at very low power recorded on blackened degraded samples showed the presence of a mixture of the two polymorphs of lead (IV) dioxide, plattnerite (β‐PbO2), and scrutinyte (α‐PbO2), as degradation products of lead‐based pigments. On these samples, no evidence of white lead was found, although a white lead conversion treatment had been applied on the paintings. The degradation of red lead (Pb3O4) into a mixture of plattnerite, scrutinyte, and anglesite (PbSO4) was demonstrated in some darkened samples. Furthermore, the degradation of haematite (Fe2O3) with the formation of magnetite (Fe3O4) and coquimbite (Fe2(SO4)3·9H2O) was also identified as responsible for the blackening of the paintings. The influence of original materials and environmental and anthropogenic factors such as the valley's orography and the presence of contaminating agents (SOx) is discussed to explain the decay phenomena. [ABSTRACT FROM AUTHOR]

Libyan Desert Glasses (LDGs) and Darwin Glasses (DGs) are impact glasses produced by the impact of an extraterrestrial body into the Earth million years ago. LDGs were formed in the Libyan Desert (Africa) and DGs in Tasmania (Australia). From their formation, they have suffered terrestrial weathering processes due to their interaction with the environment. This is the first work that has evaluated their weathering processes according to their composition, the surrounding environment, and the climate. An innovative methodology based on the leaching of organic and inorganic ions and chemical modeling simulations was employed. Inductively coupled plasma-mass spectrometry (ICP-MS), ionic chromatography (IC), and solid-phase microextraction (SPME), and head space (HS) injections coupled to gas chromatography and mass spectrometry (GC-MS) detection were used. As a result, soluble organic compounds such as oxalates, n-hexadecanoic acid, and 4-chlorobenzalacetone were detected. The inorganic ions suffered a similar process, going inside the body of glasses and precipitating the corresponding salts when water evaporated. As these compounds are polar, they were probably transported by infiltration waters from outside the glasses, remaining inside in the pores, cavities, or cracks of the glasses during thousands of years. In the case of the DGs, it could be observed that under the oxidizing conditions of the terrestrial atmosphere, sulfides present in some samples transformed into sulfates. Finally, this methodology could be applied in other extraterrestrial materials discovered in deserts, ice fields, or in locations with great living activity like those of Tasmania. [ABSTRACT FROM AUTHOR]

Most of the wall paintings from Pompeii are decorated with red and yellow colors but the thermal impact of 79 AD Mount Vesuvius eruption promoted the partial transformation of some yellow-painted areas into red. The aim of this research is to develop a quantitative Raman imaging methodology to relate the transformation percentage of yellow ochre (goethite, α-FeOOH) into red color (hematite, α-Fe2O3) depending on the temperature, in order to apply it and estimate the temperature at which the pyroclastic flow impacted the walls of Pompeii. To model the thermal impact that took place in the year 79 AD, nine wall painting fragments recovered in the archeological site of Pompeii and which include yellow ochre pigment were subjected to thermal ageing experiments (exposition to temperatures from 200 to 400 °C every 25 °C). Before the experiments, elemental information of the fragments was obtained by micro-energy dispersive X-ray fluorescence (μ-ED-XRF). The fragments were characterized before and after the exposition using Raman microscopy to monitor the transformation degree from yellow to red. The quantitative Raman imaging methodology was developed and validated using synthetic pellets of goethite and hematite standards. The results showed almost no transformation (0.5% ± 0.4) at 200 °C. However, at 225 °C, some color transformation (26.9% ± 2.8) was observed. The most remarkable color change was detected at temperatures between 250 °C (transformation of 46.7% ± 1.7) and 275 °C (transformation of 101.1% ± 1.2). At this last temperature, the transformation is totally completed since from 275 to 400 °C the transformation percentage remained constant. [ABSTRACT FROM AUTHOR]

Underwater Cultural Heritage understands all traces of human existence having a cultural, historical, or archaeological character, which have been partially or totally underwater, in periodic or continuous forms for at least 100 years, according to UNESCO. This work is focused on two pieces extracted in 1999 from a shipwreck located in Bakio (Basque Country, Northern Spain). The two analyzed pieces were an iron anchor and a swivel gun, both exposed in Bakio's Town Hall after their restoration in 2005. The aim of this work is to study the elemental composition of archaeological metallic pieces extracted from underwater and the degradation processes that affect them. For that purpose, nondestructive analytical techniques were employed. Concretely, Raman spectroscopy and X‐ray fluorescence spectroscopy were used to check the conservation state and to identify the raw materials that were used in the manufacture of those pieces. The analyses concluded that both artifacts were manufactured in cast iron, although the composition of the raw materials was not exactly the same. The main decaying compound was lepidocrocite (γ‐FeO(OH)), a highly reactive iron phase that increases the corrosion rate of the artifacts, though other iron oxy‐hydroxides were also detected in minor amounts. This compound together with the also found akaganeite (β‐Fe2(OH)3Cl) were probably the responsible of the continuous oxidation of the metallic pieces, which are in a poor conservation state. Therefore, the applied treatment was not suitable for these pieces. The two underwater metallic pieces exposed in Bakio's Town Hall have studied in this work. Both pieces were mechanically treated in 2005, and to determine the current conversation state and to check if that treatment was appropriate for this kind of pieces, Raman spectroscopy was used. This word confirms that Raman spectroscopy is a suitable technique to analyze underwater metallic pieces and to detect remains of past conservation treatments. [ABSTRACT FROM AUTHOR]

The Raman spectra of the Na2SO4‐K2SO4‐H2O system are not well‐defined in the literature. Specifically, the proper identification of sodium and potassium sulphate (aphthitalite or glaserite, K3Na(SO4)2) and anhydrous sodium sulphate (thenardite, Na2SO4) is particularly problematic because their vibrational profiles present the same main Raman peak at 993 cm−1 and very similar low frequency bands. As proved in bibliography, the similarity of their spectra can often lead to uncertain or erroneous identifications. Considering that aphthitalite and thenardite can be found as degradation products on built heritage materials and the degree of danger associated to them is not the same, being the second one the most harmful, the resolution of this problem has a critical importance. For this reason, in the present work, the Raman spectra of aphthitalite and thenardite are deeply studied to identify the vibrational fingerprints enabling their correct identification. The results here summarized and provided by two different Raman instruments highlight that the spectrum of aphthitalite displays characteristic bands at 1,084 and 1,202 cm−1. In contrast, the bands at 1,100, 1,129, and 1,152 cm−1 seem to be characteristic of thenardite. Furthermore, when those secondary bands are not observed or mixtures of both compounds are present, the ratio between their most intense bands at 452 and 993 cm−1 is the key for their correct characterization. On the whole, this study fills the gaps observed in literature and gives the solution for the correct identification of aphthitalite and thenardite even when secondary bands are not observed. This study fills the gaps observed in literature in the Raman spectra of the Na2SO4‐K2SO4 system by 532 and 785‐nm excitation lasers, which has a relevant importance in built heritage studies, giving the solution for the correct identification of aphthitalite and thenardite even when secondary bands are not observed. [ABSTRACT FROM AUTHOR]

Quantification with nondestructive techniques is not very well developed in the field of Cultural Heritage despite its interest. In the last decades, several works have been published using Raman spectroscopy for quantifying. However, depending on the methodology used, the information provided by this technique is not complete, and the results could lead to misunderstanding when dealing with unknown samples. In this work, a novel double quantification using Raman imaging (its representativeness would be higher than point‐by‐point analysis) and Laser Induce Breakdown Spectroscopy (LIBS) analyses is presented for analysis of Cultural Heritage samples. Several dolomitic marble samples, with some calcite impurities, covered or not by a calcium oxalate (whewellite, CaC2O4·H2O) layer were analysed in order to optimize the novel methodology. The agreement between the quantitative results from the independent analyses of the Raman Image data and the LIBS data is consistent within the uncertainty arising from both techniques. Further, the same methodology was applied on the same samples but using point‐by‐point Raman analysis with portable instruments, and portable LIBS information, showing again a great agreement between them and with the results obtained using the laboratory instruments. The use of nondestructive techniques such as Raman spectroscopy in Cultural Heritage has proven to be a useful tool for quantifying. Both portable and bench Raman equipments gave comparable results, important fact for future quantitative analysis in situ. Moreover, its combination with quantitative results of a portable LIBS system was also comparable. This last technique provided the hydration of the sample as well. [ABSTRACT FROM AUTHOR]

Raman microscopy is a molecular technique that is able to detect compounds that are present in the samples at minor/trace levels thanks to the precise focusing on particles of interest. The detection will also depend on the Raman scattering of the measured compound. Moreover, due to the nondestructive character of the measurements, this technique is one of the most used when samples under study belong to the arts and archaeological fields. Among the different archaeological sites in the world, Pompeii is one of the most important ancient cities. In this work, Raman microscopy—supported by X‐ray diffraction—has been used to detect traces of mineralogical phases of volcanic origin and contaminations in red and yellow ochre pigments. These samples were buried for thousands of years and recovered from the archaeological site of Pompeii in their original bowls. On the one hand, regarding the characteristic mineral phases of volcanic origin, the obtained results showed the presence of langite [Cu4 (SO4)(OH)6·2H2O], jarosite [KFe3 (SO4)2(OH)6], atacamite [Cu2Cl (OH)3], and anatase (β‐TiO2), a polymorph of titanium oxide found in igneous rocks. On the other hand, contamination compounds such as Egyptian or Pompeian blue (CaCuSi4O10) and huntite [Mg3Ca (CO3)4] were also identified. Some of the compounds identified by micro‐Raman spectroscopy could not be detected using X‐Ray diffraction and vice versa. Therefore, it was corroborated the necessity of using more than one unique technique in order to obtain a complete information about the molecular composition of the ochre pigments under study. Raman microscopy was used in order to detect contaminations and characteristic volcanic compounds.It was the first time that volcanic compounds such as langite, anatase, and atacamite were detected in Pompeian pigments.Egyptian blue and huntite were detected by Raman microscopy but not by XRD, pointing out that their concentration in the pigment composition was lower than 5%, which means that they are present due to a contamination. [ABSTRACT FROM AUTHOR]

Impact glasses are rich silica melted formed at high temperature and pressure by the impact of an extraterrestrial body on Earth. Here, Libyan Desert glasses (LDGs) and Darwin glasses (DGs) were studied. Two non-destructive analytical techniques were used to detect and characterize organic compounds present in their inclusions: Raman spectroscopy and scanning electron microscopy coupled to energy-dispersive X-ray spectroscopy (SEM-EDS). Phytoliths, humboldtine, palmitic acid, myristic acid, oleic acid, 4-methyl phthalic acid, and S-H stretching vibrations of amino acids were identified. The presence of these particular organic compounds in such materials has not been reported so far, providing information about (a) the ancient matter of the area where the impact glasses were formed, (b) organic matter belonging to the extraterrestrial body which impacted on the Earth, or (c) even to current plant or bacterial life, which could indicate an active interaction of the LDG and DG with the surrounding environment. Moreover, the identification of fullerene allowed us to know a pressure (15 GPa) and temperatures (670 K or 1800-1900 K) at which samples could be subjected. [ABSTRACT FROM AUTHOR]

In this work, analytical and chemical imaging tools have been applied to the study of a gilded spur found in the medieval necropolis of Erenozar (Bizkaia, Spain). As a first step, a lot of portable equipment has been used to study the object in a non-invasive way. The hand-held energy-dispersive X-ray fluorescence equipment allowed us to characterize the artefact as a rare example of an iron matrix item decorated by means of a fire gilding technique. On the other hand, the use of a portable Raman system helped us to detect the main degradation compounds affecting the spur. Afterwards, further information was acquired in the laboratory by analysing detached fragments. The molecular images obtained using confocal Raman microscopy permitted us to characterize the stratigraphic succession of iron corrosions. Furthermore, the combined use of this technique with a scanning electron microscope (SEM) was achieved owing to the use of a structural and chemical analyser interface. In this way, the molecular characterization, enhanced by the magnification feature of the SEM, allowed us to identify several micrometric degradation compounds. Finally, the effectiveness of one of the most used desalination baths (NaOH) was evaluated by comparing its effects with those provided by a reference bath (MilliQ). The comparison proved that basic treatment avoided any side effects on the spur decorated by fire gilding, compensating for the lack of bibliographic documentation in this field.This article is part of the themed issue ‘Raman spectroscopy in art and archaeology’. [ABSTRACT FROM AUTHOR]

Punta Begoña Galleries were built in 1918 in Getxo (Basque Country, North of Spain) but were abandoned in 1960. Nowadays, their conservation state is very poor. In this work, portable Raman spectroscopy was applied to evaluate the original composition and possible deterioration products of the mortars used in the inner walls and those covering the concrete of the ceilings allowing us to select the most appropriate sampling points. In the laboratory, Raman microscopy and Raman imaging, assisted with scanning electron microscopy equipped with an energy dispersive spectrometer (SEM-EDS), X-ray diffraction and energy dispersive X-ray fluorescence (ED-XRF) imaging, allowed to identify the key compounds to understand the deterioration processes taking place in the mortars of the galleries. The main components of the mortars from the walls were calcite and gypsum. In some cases, alite (Ca3SiO5) and belite (Ca2SiO4) were identified; these components are characteristic of Portland cement clinker. The main components of the mortar covering the concrete were calcite, quartz, aragonite and gypsum. The aragonite identification confirmed the use of beach sand as the aggregate in the mortar. The concrete from the ceiling of the lower gallery is covered with three different mortar layers; the outermost layer is covered with a black crust. In the three mortars, the main components are similar to those used in the mortar covering the concrete from the upper gallery. Thanks to Raman, ED-XRF and SEM-EDS imaging, it was possible to map the distribution of the main components through the three mortar layers and also to identify the presence of dolomite {[CaMg(CO3)2]}, which was not possible to detect following single-point micro-Raman analyses. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The presence of salt efflorescence is one of the main causes of deterioration of building materials. Raman spectroscopy can be used not only to identify the different compounds present in such salts but also for the semiquantification of such salt deposits based on the use of external calibration curves. Normally, this method takes time for the preparation of pellets composed of both mixtures of standard and real samples. In the present work, we propose an innovative approach for semiquantification of salts in the solid state by portable micro-Raman spectroscopy. It is based on the use of the palme software (From Molecules to Nano-objects: Reactivity Interactions and Spectroscopy-University Pierre and Marie Curie, Paris) that has been developed in order to obtain the quantitative information from the vibrational spectrum by using a multivariate linear regression approach. It considers the mixture spectra as a linear combination of the suspected pure material spectra. The aim of this work is to apply palme software to the study of pellets of standard samples composed of mixtures of calcium carbonate, gypsum and potassium nitrate at different concentrations in order to verify the reliability of this method by comparing the results with those obtained through the construction of calibration curves. Moreover, both methodologies have been tested on real efflorescence salts sampled in the San Esteban Church (Ribera de Valderejo, Basque Country, Spain). This research shows that the method based on the treatment of Raman spectra with palme software allows to obtain in situ semiquantitative results in a much shorter time (minutes in fact), being comparable in quality with those obtained with the external calibration curve method. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The 8th edition of the International Congress on the Application of Raman Spectroscopy in Art Archeology (RAA 2015) was held in Wroclaw (Poland) from 1 to 5 September 2015, with three Plenary Lectures, eight Trendsetting Talks, 37 Oral Presentations and 34 Poster Presentations. The number of active participants was 113 delegates from 22 countries among the 250 authors that presented at least one work. [ABSTRACT FROM AUTHOR]

The paint stratigraphy of the two clock faces from the tower clock of the Government Palace in Helsinki (Finland) was analysed in order to determine their original colour before restoration works. Paint cross-section samples from both clock faces were analysed by confocal Raman microscopy and scanning electron microscopy coupled to an energy dispersive X-ray spectrometer (SEM-EDS). The results revealed the complex superimposition of paint layers applied over the original black colour. FTIR/ATR analyses proved that the original paint was prepared with linseed oil-resin media. Most likely not all of the different layer colours were visible. Some of the layers were likely to have been a primer or for rust protection. [ABSTRACT FROM AUTHOR]

Raman spectroscopy, including in-situ and laboratory analyses, were carried out in beachrock outcrops located in temperate latitude (Arrigunaga beach, Bilbao Estuary, North of Spain) to characterise the wide variety of sediments and wastes trapped within the cements. In the examined beachrocks (coastal sedimentary structures formed in the intertidal zone through the early precipitation of carbonates) the presence of abundant slag and anthropogenic wastes is noticeable. In-situ Raman analysis revealed the presence of cristobalite (SiO2), tephroite (Mn2SiO4), quartz (SiO2), rhodonite (MnSiO3), labradorite (Ca,Na)(Si,Al)4O8, hematite (α-Fe2O3), gypsum (CaSO4·2H2O) and amorphous carbon (C) as the main constituents in the trapped materials. Those were also identified off site together with other phases such as limonite (FeO(OH)·nH2O), lepidocrocite (γ-FeOOH), arsenopyrite (FeAsS), fayalite (Fe2SiO4) and anatase (TiO2). As secondary compounds, portlandite (Ca(OH)2), C-S-H (Ca3Si2O7·3H2O), gypsum and possibly ettringite (3CaO·Al2O3·3CaSO4·32H2O) were identified only in-situ, and a possible evolution to the more stable thaumasite (3CaO·SiO2·CO2·SO3·15H2O) was found in the laboratory analyses. Therefore, the applied methodology and specifically the in-situ Raman spectroscopy analyses resulted particularly valuable, allowing an accurate description of the trapped materials and the compounds formed by hydration and/or sulphate attack (probably from the high level of atmospheric aerosols coming from seawater or industrial activity nearby), giving an insight of the complexity of the examined outcrops. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]