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Tourmaline from the Solnechnoe hydrothermal granitoid-related tin deposit in the Khabarovsk Krai, Russian Far East has been studied with electron microprobe, infrared and Mössbauer spectroscopy. Tourmaline formed in three distinct stages with different types of chemical substitution. Tourmaline from the first unmineralised stage is classified as dravite or schorl, which could be enriched locally in Ca, the X -site vacancy and F. This tourmaline is characterised by the Fe ↔ Mg and X vacancy + Al ↔ Na + Fe substitutions. The second, molybdenum-stage tourmaline, is schorl–dravite and fluor-schorl–fluor-dravite enriched in Ca, and a few compositions belong to the calcic group. The predominant substitution is Ca + Mg ↔ Na + Al. The third, tin-stage tourmaline, is classified as schorl–dravite with some tourmalines being fluor-schorl, oxy-schorl, foitite and magnesio-foitite. The tin-stage tourmaline is characterised by the substitutions Fe 2+ ↔ Mg, Al tot + O 2– ↔ Fe 2+ + OH – , and Fe 3+ ↔ Al tot . An increase of the Fe 3+ /Fe tot value from 3–9% in the molybdenum stage to 12–16% in the tin-stage tourmalines indicates an increase in oxidation potential, which possibly contributed to cassiterite deposition. Comparison of tourmalines from greisen, porphyry and intrusion-related tin deposits worldwide shows they differ in primary chemical substitutions so can be characterised by this mechanism. The Fe 3+ /Fe tot value in tourmaline also appears to be one of the indications for the tin deposit type. The Fe 3+ /Fe tot value increases from <10% in greisen tourmaline through 15% in tourmaline from intrusion-related deposits to 20% in tourmaline from porphyry deposits.

Distinctive magmatic-hydrothermal, tourmaline-rich features have developed in the Heemskirk and Pieman Heads granites from western Tasmania, Australia. They are categorized as tourmaline-rich patches, orbicules, cavities, and veins, based on their distinctive morphologies, sizes, mineral assemblages, and contact relationships with host granites. These textural features occur in discrete layers in the roof zone of granitic sills within the Heemskirk and Pieman Heads granites. Tourmaline patches commonly occur below a tourmaline orbicule-rich granitic sill. Tourmaline-filled cavities have typically developed above the tourmaline-quartz orbicules in the upper layer of the white phase of the Heemskirk Granite. Tourmaline-quartz veins penetrate all exposed levels of the granites, locally cutting tourmaline orbicules and cavities.The tourmalines are mostly schorl (Fe-rich) and foitite, with an average end-member component of schorl45 dravite6 tsilaisite1 uvite0 Fe-uvite3 foitite31 Mg-foitite4 olenite10 Element substitutions of the tourmalines are controlled by FeMg-1, YAlX∎(R2+Na)-1, and minor YAlO(R2+OH)-1 (where R2+ = Fe2+ + Mg2+ + Mn2+) exchange vectors. Several trace elements in tourmaline have consistent chemical evolutions grouped from tourmaline patches, through orbicules and cavities, to veins. There is a progressive decrease of most transition and large ion lithophile elements, and a gradual increase of most high-field strength elements. These compositional variations in the different tourmaline-rich features probably relate to element partitioning occurring in these phases due to volatile exsolution and fluxing of aqueous boron-rich fluids that separated from the granitic melts during the emplacement of S-type magmas into the shallow crust (4 to 5.5 km).Tourmalines from the Heemskirk Granite are enriched in Fe, Na, Li, Be, Sn, Ta, Nb, Zr, Hf, Th, and rare earth elements relative to the tourmalines from the Pieman Heads Granite, but depleted in Mg, Mn, Sc, V, Co, Ni, Pb, Sr, and most transition elements. These results imply that bulk compositions of the host granites exert a major control on the chemical variations of tourmalines. The trace element compositions of tourmalines from the Sn-mineralized Heemskirk Granite are different from those of the barren Pieman Heads Granite. Trace element ratios (e.g., Zn/Nb, Co/Nb, Sr/Ta, and Co/La) and Sn concentrations in tourmaline can distinguish the productive Heemskirk Granite from the barren Pieman Heads Granite.

The Prof pegmatite is located NW of Revelstoke, British Columbia, Canada on Boulder Mountain. Due to the abundance of petalite, the pegmatite is classified as a petalite subtype Li-Cs-Ta pegmatite or a Group one pegmatite. The Prof pegmatite contains a suite of minerals indicative of a highly evolved pegmatite melt including petalite, elbaite, lepidolite and Nb-Ta oxides. Four textural zones are present: (1) border; (2) intermediate, including (2.1) graphic texture dominant and (2.2) overgrowth dominant, where diverse minerals form rims around one another; (3) central; and (4) quartz. The border zone has a similar mineralogy to the intermediate zone and is interpreted to represent a chilled margin. The intermediate zone has a feldspar, mica, garnet and dravite-schorl dominant composition. The central zone hosts an evolved pegmatite core, which contains the majority of the lithium mineralisation composed of petalite, elbaite and lepidolite. The tourmaline, Nb-Ta oxides and mica within the pegmatite record the geochemical evolution of the melt from more primitive Fe- and Mg-rich minerals to a Li-, Mn- and Nb-rich assemblage indicative of a highly evolved geochemical system. The various pegmatitic textures and extremely fractionated geochemical composition of the pegmatite indicate that the melt was undercooled and crystallised rapidly. Three phases of metasomatism are recognised in the Prof pegmatite: an albitisation event observed cutting primary orthoclase; followed by a transition to a Na-Li-F-rich event mostly containing secondary albite, trilithionite and elbaites; and a sericitisation event. The Prof pegmatite has a similar mineralogy to known pegmatites at Mount Begbie, 15 km to the south, in particular the notable presence of the rare mineral qitianlingite, petalite, lepidolite and elbaite. Together, these pegmatite bodies form part of an extensive, poorly mapped pegmatite field. Additional work is required to assess the extent and nature of mineralisation within this field.

In this study, schorl was used as an effective adsorbent for ciprofloxacin removal from wastewater. The adsorption performance, mechanism and effect of metal ion on sorption were investigated. Adsorption capacity reached a maximum (8.49 mg/g) when the pH value was 5.5. The pseudo-second-order kinetic model and Freundlich model could better describe the experimental data. The negative ΔH (-22.96 KJ/mol) value showed that the adsorption process was exothermic. The results also indicated physical adsorption existed on the adsorption process, which was in agreement with the analysis of X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy. The desorption rate could reach 94%, which suggested that schorl had a good desorption and regeneration performance. Coexisting ions, such as Cu2+ and Al3+, could obviously inhibit adsorption, and the inhibition from Al3+ was significantly higher than that from Cu2+. However, the additional Zn2+ could slightly promote the adsorption.

Black tourmalines from seven granitic pegmatites (Golodnaya, Kazennitsa, Mokrusha, Kopi Mora, Zheltyye Yamy, Buzheninov Bor and Ministerskaya) related to the Murzinka pluton, Central Urals, Russia have been investigated using electron microprobe analysis, LA-ICP-MS, Raman and Mössbauer spectroscopy. Pegmatites are hosted by serpentinites and gneisses and are classified as schorl, oxy-schorl, fluor-schorl, dravite, oxy-dravite, foitite, oxy-foitite and darrellhenryite. The possible compositional evolution of tourmalines from the Ural pegmatites is as follows: Mg-rich dravite through to Fe-rich schorl, foitite and oxy-foitite to Fe- and Mn-rich darrellhenryite. The major substitutions in the tourmalines are: (1) Fe2+ ⇌ Mg; (2) Al + WO2- ⇌ Fe2+ + WOH-; (3) X-site vacancy + Al ⇌ Na + Fe2+; (4) Al + WO2- ⇌ Mg + WOH-; (5) X-site vacancy + Al ⇌ Na + Mg; and (6) Fe ⇌ Mn. Statistical processing of the trace- and major-element composition distinguished three tourmaline groups: (1) trace Co, Ni, Pb, and major Ca and Mg; (2) uni-, di- and trivalent traces (Li, Zn, Ga) and di- and trivalent majors (Al, Mn); (3) U, Th, Hf, Ta, Nb, Y, In, and Sn which correspond to tri-, tetra-, and pentavalent high-field-strength elements. Mössbauer data shows the Fe3+/Fe2+ ratios in tourmalines from pegmatites hosted by gneisses (0.05-0.18) and serpentinites (0.28-0.65), indicates different oxidising environments. Raman data are consistent with the composition of the tourmalines.

This study describes mineralogical and crystallochemical characteristics of metamorphic tourmalines from an Alpine shear zone in a Variscan metamorphic rock sequence from the Maramures region in the northern part of the East Carpathians. We use this mineral to unravel aspects of the evolution of the tourmaline bearing host rocks and compare the crystallo-chemical characteristics to other tourmalines from Alps. Petrographic and microstructural observations, as well as electron microprobe analyses on several zoned tourmalines and associated minerals (mica, feldspar) from mylonitic schist of the Rebra terrane (Maramureș Mountains), indicate that the pre-kinematic tourmalines belong to the alkali group (Na dominant), hydroxyl dominated on the crystallographic W-site and can be assigned to the species dravite and schorl. The tourmaline-bearing rocks have a metasedimentary protolith. The analysed porphyroblasts, rotated by simple shear, show corroded rim that are interpreted to have formed due to pressure release. Three main compositional zones were evidenced on a tourmaline porphyroblast: a core zone and two asymmetrically arranged inclusion-poor/free rims, all formed in pre-alpine prograde metamorphic conditions. Based on mineral microstructural relations and geothermobarometry (tourmaline–muscovite, tourmaline–plagioclase geothermometry and phengite geobarometry), the metamorphic peak conditions of the investigated Rebra terrane were evaluated to have been at a temperature of ca. 590 to 620 ± 22 °C and P = 5.5 - 6.0 ± 0.5 kbar. By observing dynamically recrystallized microstructures in quartz and feldspar in the shear zone a temperature of 350 - 400 °C was estimated and the quartz paleopiezometry outlined a differential stress of about 1.5 kbar that implied only minor chemical change in tourmaline outer zone.

Oxy-dravite, ideally Na(Al2Mg)(Al5Mg)(Si6O18)(BO3)3(OH)3(O), was found in a composition near its ideal end-member at the Beluga occurrence, Nunavut territory, Canada. It occurs in retrograde albite-muscovite-corundum-calcite domains in a calc-silicate rock. This uncommon oxy-dravite occurs as dark brown, equant to short-prismatic, idiomorphic crystals with vitreous lustre and up to ca. 4 × 3 cm in size. The oxy-dravite is optically uniaxial (-), with ω = 1.6453(5) and (open e) = 1.6074(18); its calculated density is 3.069 g.cm-3 with a compatibility index of 0.016. The Beluga oxy-dravite has trigonal symmetry, space group R3m with a = 15.9121(2) Å, c = 7.1788(10) Å, V = 1574.12(5) Å3 and Z = 3. The crystal structure was refined to R1 = 1.45 using 1613 unique reflections. The empirical crystal-chemical formula is X(Na0.88Ca0.08∎0.03K0.01)Y(Al1.49Mg1.31Fe0.15Ti0.04 Z n0.01)Z( Al5.42Mg0.58)T(Si5.84Al0.16O18)B(BO3)3V(OH2.95O0. 05)W(O0.84OH0 .01F0.15). Oxy-dravite in nature commonly occurs in a solid solution with foitite, schorl and oxy-schorl. At the Beluga occurrence, its minor contents of Al, vacancy [∎], and Ca are most likely compensated by (∎Al)(NaR2+)-1 and (CaMg)(NaAl)-1 exchanges of the oxy-magnesio-foitite and magnesio-lucchesiite components. The Beluga occurrence of oxy-dravite is characterised by an Mg-rich environment related to a metamorphic overprint of the original sedimentary sequence. This sequence of marine dolomitic argillaceous marl was influenced by (B,Cl)-rich fluids, probably proximally-derived from mineral breakdown reactions in the calc-silicate during the retrograde stage of metamorphism. The locality is a rare example of a tourmaline + corundum assemblage.

The extensive P-T stability and the high chemical variability of tourmaline (Tur) together with its common occurrence in metasediments proves its high potential for petrological and (isotope) geochemical studies on fluid-rock interaction in subduction- and collision-related rocks. This paper reviews the occurrence, major element chemistry and boron isotopic composition of Tur in high- and ultrahigh-pressure metamorphic (UHPM) rocks. In addition, it presents a new discovery of coesite-bearing Tur (schorl) from the Erzgebirge (Germany), as well as Tur (dravite) related to the retrograde history of coesite- and diamond-bearing rocks from the Erzgebirge and the Kokchetav Massif (Kazakhstan). The scarce data on worldwide occurrences of (U)HPM Tur reveal a high occupation of the crystallographic X-site (dominated by Na) and the possible presence of excess B, with little further distinctiveness in its major element composition when compared with Tur from medium-grade rocks. High K2O contents in Tur are probably not related to UHP growth or equilibration. The B isotopic composition of (U)HPM Tur ranges in δ11B from -16 to +1 per mil, with many samples in or below the range of continental crust. In contrast, Tur formed during retrograde fluid influx typically shows high δ11B values (up to +28 per mil), suggesting heavy-B fluids infiltrating the exhuming (U)HPM units. Coesite inclusions in Tur, characterized by Raman spectroscopy, are regarded as the best indicator for its UHP stability.