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Italian medieval and Renaissance manuscript cuttings and miniatures from the Victoria and Albert Museum were analyzed by Raman microscopy to compile a database of pigments used in different periods and different Italian regions. The palette identified in most manuscripts and cuttings was found to include lead white, gypsum, azurite, lazurite, indigo, malachite, vermilion, red lead, lead tin yellow (I), goethite, carbon, and iron gall ink. A few of the miniatures, such as the historiated capital “M” painted by Gerolamo da Cremona and the Petrarca manuscript by Bartolomeo Sanvito, are of exceptional quality and were analyzed extensively; some contained unusual materials. The widespread usage of iron oxides such as goethite and hematite as minor components of mixtures with azurite is particularly notable. The use of a needle-shaped form of iron gall ink as a pigment rather than a writing material was established by both Raman microscopy and x-ray fluorescence spectroscopy for the Madonna and Child by Franco de’ Russi.

The mineral exploration industry requires new methods and tools to address the challenges of declining mineral reserves and increasing discovery costs. Laser-induced breakdown spectroscopy (LIBS) represents an emerging geochemical tool for mineral exploration that can provide rapid, in situ, compositional analysis and high-resolution imaging in both laboratory and field and settings. We demonstrate through a review of previously published research and our new results how LIBS can be applied to qualitative element detection for geochemical fingerprinting, sample classification, and discrimination, as well as quantitative geochemical analysis, rock characterization by grain size analysis, and in situ geochemical imaging. LIBS can detect elements with low atomic number (i.e., light elements), some of which are important pathfinder elements for mineral exploration and/or are classified as critical commodities for emerging green technologies. LIBS data can be acquired in situ, facilitating the interpretation of geochemical data in a mineralogical context, which is important for unraveling the complex geological history of most ore systems. LIBS technology is available as a handheld analyzer, thus providing a field capability to acquire low-cost geochemical analyses in real time. As a consequence, LIBS has wide potential to be utilized in mineral exploration, prospect evaluation, and deposit exploitation quality control. LIBS is ideally suited for field exploration programs that would benefit from rapid chemical analysis under ambient environmental conditions. Minerals 2019, 9, 718 2 of 45 government to search for additional mineral resources in green-field (i.e., remote) and brown-field (i.e., near mine) exploration environments [7][8][9]. However, the global trends of declining mineral reserves for many commodities and increasing discovery costs [3,4,10] suggest that exploration investment is insufficient and/or is not being deployed in the most effective manner possible. Both trends are also occurring at a time when new mineral deposit discoveries tend to be deeper, covered, and/or more remote, which are unlike near-surface mines that were often found, at least initially, by prospectors [4,[7][8][9]11].To address increasing demand and declining mineral reserves from deeper and more challenging deposits, the mineral exploration industry had to evolve and innovate by adopting new, cost-effective methodologies and technologies. For example, new conceptual models provide a predictive framework to identify the kinds of large-scale geological environments that should be considered the most prospective for finding additional mineral resources in greenfield areas of sparse geological data [12-15]. The ore system concept, which includes all of the geological processes required to transport and concentrate ore components from source to ore (i.e., drivers, sources, pathways, and traps), is one such predictive framework [12][13][14]16]. Because each of the required ore-forming components is manifested in the rock record as chan...

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A broad suite of geological materials was studied a using a handheld laser‐induced breakdown spectroscopy (LIBS) instrument. Because LIBS is simultaneously sensitive to all elements, the full broadband emission spectrum recorded from a single laser shot provides a ‘chemical fingerprint’ of any material – solid, liquid or gas. The distinguishing chemical characteristics of the samples analysed were identified through principal component analysis (PCA), which demonstrates how this technique for statistical analysis can be used to identify spectral differences between similar sample types based on minor and trace constituents. Partial least squares discriminant analysis (PLSDA) was used to distinguish and classify the materials, with excellent discrimination achieved for all sample types. This study illustrates through four examples (carbonate minerals and rocks, the oxide mineral pair columbite–tantalite, the silicate mineral garnet and native gold) how portable, handheld LIBS analysers can be used for real‐time chemical analysis under simulated field conditions for element or mineral identification, plus such applications as stratigraphic correlation, provenance determination and natural resource exploration.

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A series of wall paintings dating from the Romanesque period to the 16th century were uncovered during restoration projects at the church of Santa Eulàlia of Unha in the Val d'Aran. This study centres on the use of complementary spectroscopic techniques to examine comprehensively the pigments, binders and other materials associated with these mural paintings. These include Raman microscopy, far and mid-Fourier transform infrared (FTIR) spectroscopy both with synchrotron radiation (SR), as well as optical microscopy and scanning electron microscopy (SEM-EDS), and build upon earlier SR-X-ray diffraction studies. Traditional materials such as hematite, goethite, vermilion, red lead, carbon black and calcite were identified, but the artists' palette varied with the period. The blue pigment identified in the Romanesque frescoes was determined to be aerinite, a rare Fe(II)/Fe(III)-containing aluminosilicate found locally in the Pyrenees region. Electronic, Raman and far-SR-FTIR spectra of this pigment are presented for the first time in the context of a work of art. The presence of some nitrates, sulphates and oxalates found in the mural paintings is commented upon.