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Raman spectroscopy represents a new way to obtain detailed comprehensive information on heavy-mineral assemblages. In this work are presented several examples from major Alpine (Po River) and Himalayan (Ganga and Brahmaputra Rivers) fluvio-deltaic sands. Our attention was focused on the chemical properties of garnet, which is a widespread mineral in orogenic sediments, easy to be identified, and relatively stable during both equatorial weathering and intrastratal dissolution. Garnet grains were studied in different samples representative of various depositional environments (fluvial bar, fluvial levee, shoreface, beach berm, eolian dune), in order to investigate specifically the hydraulic behaviour of grains with different density in different hydrodynamic conditions. Raman spectra and semi-quantitative analysis of Raman shifts allowed us to rapidly determine the distribution of garnet types in each sample in order to obtain chemical composition, to calculate the density of each garnet, and finally to infer their respective provenance. This manuscript presents one possible application of the "MIRAGEM" method described by Bersani et al. in this volume. References, data sets and details on the analytical routine are widely explained in the above mentioned work.

Green colored samples on wall paintings and green powder from a pigment pot found in Pompeii area are investigated by micro-Raman, FT-IR and, for one sample, SEM-EDX. To obtain the green color, green earths and malachite were used, together with mixture of Egyptian blue and yellow ochre. The mineralogical identification of the green earths has been attempted through the comparison of the vibrational features, discriminating between celadonite and glauconite spectra. Traces of a modern synthetic pigment containing copper phthalocyanine were found in a fresco fragment.

Minerals, as raw structural materials or pigments, play a fundamental role in archaeometry, for the understanding of nature, structure and status of an artefact or object of interest for cultural heritage. A detailed knowledge of the mineral phases is crucial to solve archaeological problems: Raman spectroscopy is a powerful investigation technique and has been applied extensively in the last 30 years on mineral identification and on pigment degradation. Here we report an updated review, covering the last decade, of the applications of Raman techniques to issues in which raw minerals, including mineral pigments, are involved. Particular attention is devoted to cases where the Raman analysis of minerals is deeper than a simple identification of the phases present in an archaeological or artistic object. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Albertiniite, Fe2+(SO3) · 3H2O, is a new Fe2+ sulfite trihydrate, related chemically to gravegliaite. It occurs at the Monte Falo Pb-Zn mine near Coiromonte, in the Anneno Municipality, Verbano-Cusio-Ossola Province, Italy. It is an intemiediate product of oxidation between iron sulfides and sulfates, fonning monoclinic, colourless to pale yellow, transparent crystals with a vitreous lustre. The mineral occurs associated with stolzite, pyromorphite, hinsdalite, plumbogummite, gibbsite, scheelite and jarosite on brittle fractures of quartz veins or chlorite-schist. Albertiniite is optically biaxial (+) with 2V(meas) ≈ 40° and 2V(calc) = 66°. The measured refractive indices, using sodium light (589 nm) are: α = 1.612(2)°, β = 1.618(2)° and γ = 1.632(2)°. The optical axis plane is parallel to the perfect {010} cleavage plane. It is non-fluorescent under shortwave (254 nm) or longwave (366 nm) ultraviolet light. The calculated density is 2.469 g cm-3 (from the crystal-structure refinement), or 2.458 g cm-3 (from the chemical analysis and the single-crystal unit-cell parameters). The empirical formula is (average of 16 spots and based on 3 anhydrous oxygen apfu (Fe2+0.774Mn2+0.282Ca0.001Mg0.001Na0.003)∑1.061(S0.971O3) · 2.84H2O, with the H2O content calculated by difference to 100 wt.%. Albertiniite is monoclinic, with space group P21/n. Its unit-cell parameters are: a = 6.633(1), b = 8.831(1), c = 8.773(1) Å, β = 96.106(8)° and V = 511.0(1) Å3,with Z = 4.The eight strongest measured lines in the powder X-ray diffraction pattern are [d in Å, (I/I0), (hkl)]: 4.072 (100) (1̅11), 3.539 (93) (1̅12), 5.533 (27) (1̅01), 6.167 (14) (011), 2.830 (14) (211), 4.998 (14) (101), 4.353 (12) (111) and 3.897 (12) (012). The mineral, which has been approved by the CNMNC, number IMA2015-004, is named albertiniite in honour of Claudio Albertini, an Italian mineral collector and expert in the systematic mineralogy of the Alps and pegmatites. [ABSTRACT FROM AUTHOR]

The crystal chemistry of a natural, gem-quality, blue-grey Zn-rich spinel crystal from Jemaa, Kaduna State, Nigeria, was studied using electron microprobe, single-crystal X-ray diffraction, optical absorption and Raman spectroscopies. The composition of the crystal approaches the gahnite endmember (ZnAl2O4), ∼94 mol.%, with the remainder being dominated by a hercynite component (FeAl2O4). The unit-cell dimension is 8.0850(3) Å and the tetrahedral and octahedral bond distances are determined as T-O 1.9485(6) Å and M-O 1.9137(3) Å . Crystal chemical analysis resulted in the empirical structural formula T(Zn0.94Fe2+0.03Al0.03)M(Al1.96Fe2+0.03Fe3+0.0.1)O4, which shows Zn and Al almost fully ordered in the tetrahedrally and octahedrally coordinated T and M sites, respectively. Raman spectra obtained using the excitation of the blue 473.1 nm line of a Nd:YAG laser display three of the five Raman-active modes predicted for the general oxide spinel group of minerals. These are the Eg mode at 420.6 cm-1 and the T2g modes at 510 cm-1 and 661 cm-1, due to vibrations in the AlO6 octahedra. Optical absorption spectra recorded in the UV/VIS-NIR-MIR range 2000-29000 cm-1 show a dominant absorption band at ∼5000 cm-1 which is caused by spin-allowed electronic d-d transitions in Fe2+ located at the T sites. The blue-grey hue exhibited by the sample is mainly due to spin-forbidden electronic transitions in TFe2+ and to MFe2+ → MFe3+ intervalence charge transfer, and the poor saturation of the colour is due to the small concentration of Fe2+ and Fe3+. [ABSTRACT FROM AUTHOR]