https://ejm.copernicus.org/articles/ Recent articles of the journal European Journal of Mineralogy en https://doi.org/10.5194/ejm-38-545-2026 https://doi.org/10.5194/ejm-38-545-2026 <b>The impact of exsolution textures in Fe–Ti oxide minerals on crushing strategies and vanadium and titanium pre-concentration</b><br> Thomas Daniel van Gerve, Philippe Muchez, Ted Nuorivaara, and Olivier Namur<br> Eur. J. Mineral., 38, 545–556, https://doi.org/10.5194/ejm-38-545-2026, 2026<br> Vanadium ores from the Bushveld Complex contain distinct microscopic mineral textures that strongly influence how efficiently vanadium can be extracted. Our study shows that some textures tightly intergrow minerals and hinder separation, while others form coarser structures that improve processing by magnetic and flotation methods. Identifying these textures is essential for optimizing vanadium ore processing and resource use. Fri, 21 Aug 2026 22:15:54 +0200 https://doi.org/10.5194/ejm-38-531-2026 https://doi.org/10.5194/ejm-38-531-2026 <b>Belmonteite, CaMn2(AsO4)2(H2O)5 ⋅ 2H2O, a new arsenate mineral from the Mn ore deposits of the Graveglia Valley, eastern Liguria, Italy</b><br> Cristian Biagioni, Jiří Sejkora, and Zdeněk Dolníček<br> Eur. J. Mineral., 38, 531–543, https://doi.org/10.5194/ejm-38-531-2026, 2026<br> Belmonteite, CaMn2(AsO4)2(H2O)5·2H2O, is a new mineral discovered in the Mn ore deposits of eastern Liguria (Italy). Its crystal structure shows {010} layers of six-fold-coordinated Mn atoms decorated on both sides by (AsO4) groups and Ca atoms and connected through H bonds. The genesis of this mineral is related to the circulation of As-rich oxidizing fluids within the Mn ore deposits. The name honors Donato Belmonte for his contribution to the knowledge of the mineralogy of Liguria. Wed, 19 Aug 2026 22:15:54 +0200 https://doi.org/10.5194/ejm-38-519-2026 https://doi.org/10.5194/ejm-38-519-2026 <b>Fengruiite, [Ag6Sb2S7][Ag9CuS2Te2], a new Ag–Sb–Te sulfosalt mineral from the Haopinggou Ag–Pb–Zn–Au deposit, eastern Qinling, China</b><br> Yongfei Tian, Guowu Li, Ningyue Sun, Min Liu, Jingwen Mao, Yunpeng Dong, Peng Liu, Wei Jian, Wei Yao, Xiuquan Wang, and Huishou Ye<br> Eur. J. Mineral., 38, 519–530, https://doi.org/10.5194/ejm-38-519-2026, 2026<br> We studied a newly discovered silver-rich mineral from an ore deposit in central China to understand how silver is stored in nature. Using microscopy, chemical, and crystal-structure tests, we found that this mineral is a new species with a unique tellurium-rich structure. Our results show that tellurium helped trap and concentrate silver in hot mineral-forming fluids, offering new clues to how silver-rich deposits form. Thu, 13 Aug 2026 22:15:54 +0200 https://doi.org/10.5194/ejm-38-497-2026 https://doi.org/10.5194/ejm-38-497-2026 <b>A novel experimental approach to investigate element transport and isotope fractionation of Li and B in pegmatitic systems during fluid–melt interaction</b><br> Christian Ronny Singer, Harald Behrens, Ingo Horn, Martin Oeser, Stefan Weyer, and François Holtz<br> Eur. J. Mineral., 38, 497–518, https://doi.org/10.5194/ejm-38-497-2026, 2026<br> We developed a novel experimental setup to investigate the transport of Li and B between two melt reservoirs that were connected only via a fluid phase. This was used to simulate fluid exsolution occurring during late-stage pegmatite formation. We found that both Li and B were transported via the fluid, but the observed transport rates were low. It was shown experimentally that the Li isotopes fractionate between melt and fluid with the fluid being preferentially enriched in the heavier 7Li. Thu, 06 Aug 2026 22:15:54 +0200 https://doi.org/10.5194/ejm-38-491-2026 https://doi.org/10.5194/ejm-38-491-2026 <b>IMA Commission on New Minerals, Nomenclature and Classification (CNMNC) – Newsletter 92</b><br> Ferdinando Bosi, Frédéric Hatert, Marco Pasero, and Stuart J. Mills<br> Eur. J. Mineral., 38, 491–495, https://doi.org/10.5194/ejm-38-491-2026, 2026<br> Fri, 31 Jul 2026 22:15:54 +0200 https://doi.org/10.5194/ejm-38-477-2026 https://doi.org/10.5194/ejm-38-477-2026 <b>Preservation of water concentration in mantle xenoliths: a case study from Allègre and Ray Pic volcanoes (French Massif Central)</b><br> Konstantinos Thomaidis, Jannick Ingrin, Etienne Deloule, Lydéric France, and Huan Chen<br> Eur. J. Mineral., 38, 477–489, https://doi.org/10.5194/ejm-38-477-2026, 2026<br> Water in the form of hydrous-point-defect pyroxenes from mantle xenoliths is used to trace the water content in the lithospheric mantle. However, little is known about the mechanism that allows xenoliths to preserve deep hydrogen signatures. In particular, it is unknown how much of the water content of xenoliths is modified during the emplacement of lava and cooling at the surface and by the eruption mode (effusive versus explosive). In this work, we attempted to address these matters. Mon, 27 Jul 2026 22:15:54 +0200 https://doi.org/10.5194/ejm-38-461-2026 https://doi.org/10.5194/ejm-38-461-2026 <b>Thermally activated multistep alteration of Fe2+-bearing fluorophlogopite revealed by in situ Raman spectroscopy</b><br> Christian Reinberg, Stylianos Aspiotis, Thomas Malcherek, Stefan T. M. Peters, and Boriana Mihailova<br> Eur. J. Mineral., 38, 461–475, https://doi.org/10.5194/ejm-38-461-2026, 2026<br> By applying in situ high-temperature Raman spectroscopy to (OH)-- and Fe2+-bearing fluorophlogopite we show that a phonon-driven structural instability near 600 K triggers the mobilization of interlayer K+ cations, which can act as charge carriers. Above 1100 K all H+ cations delocalize and can also contribute to transport processes. Above 1300 K oxidation of Fe takes place, along with limited dehydrogenation and dehydroxylation, facilitating partial K+ leakage and structural decomposition. Wed, 22 Jul 2026 22:15:54 +0200 https://doi.org/10.5194/ejm-38-449-2026 https://doi.org/10.5194/ejm-38-449-2026 <b>Xianhuaite-(Ce), K2CeNb5O15, a new niobium mineral from the Bayan Obo deposit, China</b><br> Bo Yang, Yuan Xue, Li Yang, Ningyue Sun, Guowu Li, Junfang Yu, Guoying Yan, Jianyong Liu, Yonggang Zhao, Wenxiang Meng, Zhenyu Chen, Lei Chen, Ze Liu, Zhao Yan, Xinyu Hou, Xin Ao, and Jinlong Wang<br> Eur. J. Mineral., 38, 449–459, https://doi.org/10.5194/ejm-38-449-2026, 2026<br> Researchers studying the Bayan Obo deposit in northern China discovered an unknown mineral named xianhuaite-(Ce). The mineral contains the elements potassium, cerium, and niobium. Using microscopes, chemical analyses, and X-ray measurements, the researchers determined its structure and properties. The study shows that this mineral records the formation of rare earth and niobium ores in geological processes, improving our understanding of how these important resources formed. Tue, 21 Jul 2026 22:15:54 +0200 https://doi.org/10.5194/ejm-38-431-2026 https://doi.org/10.5194/ejm-38-431-2026 <b>Fluorine-induced melting in the Ihalainen calcite-wollastonite marble deposit, Lappeenranta, Finland</b><br> Robert F. Martin, Dirk Schumann, Markku J. Lehtinen, and Sebastian Fuchs<br> Eur. J. Mineral., 38, 431–448, https://doi.org/10.5194/ejm-38-431-2026, 2026<br> The Ihalainen deposit in Finland produces wollastonite, a silicate of calcium. It formed 1.86 x 109 years ago; 240 x 106 years later, the area was invaded by a fluorine-rich granitic magma, which interacted with the marble host. The silicate magma lost silica and alkalis; the marble melted. A fluorine-rich vapor phase mobilized niobium, tantalum, and tin to form unknown minerals. The fluid was initially CO2-dominant and then became aqueous and formed a complex assemblage of alteration minerals. Mon, 20 Jul 2026 22:15:54 +0200 https://doi.org/10.5194/ejm-38-419-2026 https://doi.org/10.5194/ejm-38-419-2026 <b>Mckelveyite group minerals – Part 5: Bainbridgeite-(NdCe), Na2Ba2NdCe(CO3)6●3H2O, a new neodymium and cerium-dominant species from Mont Saint-Hilaire, Canada</b><br> Inna Lykova, Ralph Rowe, Glenn Poirier, Henrik Friis, Kelsie Ojaste, and Stephanie Barnes<br> Eur. J. Mineral., 38, 419–429, https://doi.org/10.5194/ejm-38-419-2026, 2026<br> The paper describes bainbridgeite-(NdCe), Na2Ba2NdCe(CO3)6∙3H2O, from the famous Mont Saint-Hilaire complex, Quebec, Canada, the first known mineral with Ce and Nd atoms preferentially concentrated at two different sites of the structure Thu, 16 Jul 2026 22:15:54 +0200 https://doi.org/10.5194/ejm-38-397-2026 https://doi.org/10.5194/ejm-38-397-2026 <b>Hydrothermal quartz genesis revealed by the combination of SEM charge contrast maps, FTIR mapping, and LA-ICP-MS trace element geochemistry</b><br> Marko Bermanec, Nils B. Gies, Thomas Pettke, and Jörg Hermann<br> Eur. J. Mineral., 38, 397–417, https://doi.org/10.5194/ejm-38-397-2026, 2026<br> We investigate how trace elements are incorporated into quartz formed in magmatic–hydrothermal ore deposits, key environments for critical metal enrichment. By tracking Li, B, Al, Ti, and OH defects across crystal growth zones we reveal distinct trace element zonation patterns linked to temperature and pressure evolution during crystallization. We demonstrate that combined trace element data and mapping of quartz can be a powerful tool for understanding ore deposit genesis and prospecting ores. Mon, 13 Jul 2026 22:15:54 +0200 https://doi.org/10.5194/ejm-38-383-2026 https://doi.org/10.5194/ejm-38-383-2026 <b>Boron coordination in haplogranite glasses</b><br> Jakob Rauscher, Michael Fechtelkord, Sandro Jahn, Julie A.-S. Michaud, Draupadi Mothan, Melanie J. Sieber, Robert B. Trumbull, Franziska D. H. Wilke, Max Wilke, and Bernd Wunder<br> Eur. J. Mineral., 38, 383–396, https://doi.org/10.5194/ejm-38-383-2026, 2026<br> Boron and its isotopes, 11B and 10B, can track magmatic–hydrothermal processes, but this requires knowing how the isotopes fractionate between melt and fluid, which depends on B coordination. This is known for aqueous fluids but not for silicate melts. We determined B coordination by nuclear magnetic resonance in granitic glass with variable water content and alkali–alumina ratios. The results provide a way to estimate B coordination and melt–fluid fractionation for variable melt compositions. Thu, 09 Jul 2026 22:15:54 +0200 https://doi.org/10.5194/ejm-38-373-2026 https://doi.org/10.5194/ejm-38-373-2026 <b>Yttrotungstite-(Nd), a new mineral species from the Nyakabingo tungsten mine, Kigali, Rwanda</b><br> Frédéric Hatert, Simon Philippo, Pietro Vignola, and Maël Guennou<br> Eur. J. Mineral., 38, 373–382, https://doi.org/10.5194/ejm-38-373-2026, 2026<br> Yttrotungstite-(Nd) is a new mineral species discovered in the Nyakabingo tungsten mine, Kigali, Rwanda. The mineral occurs in the oxidized zones of the deposit, where it forms tiny yellow-orange tabular crystals that reach a length of maximum of 100 µm, and frequently form radiated groups. The dominant form is {010}, and a twinning has been observed parallel to (001). Electron microprobe analyses and structural data, confirming that the species belongs to the yttrotungstite group. Tue, 07 Jul 2026 22:15:54 +0200 https://doi.org/10.5194/ejm-38-353-2026 https://doi.org/10.5194/ejm-38-353-2026 <b>Dehydration reactions in guano-derived minerals: the taranakite-to-francoanellite transformation</b><br> Yuri Galliano, Nicola Campomenosi, Fabio Bellatreccia, Donato Belmonte, Jo De Waele, and Cristina Carbone<br> Eur. J. Mineral., 38, 353–372, https://doi.org/10.5194/ejm-38-353-2026, 2026<br> Deposits of bat guano in cave environments host diverse assemblages of secondary minerals, which can go through partial dehydration processes in response to varying environmental conditions. In this article, we investigate the thermodynamics and kinetics which lead guano-derived taranakite to lose part of its structural water and transform into francoanellite. Our results allow us to present evidence-based hypotheses to explain the occurrence of the latter in natural environments. Mon, 22 Jun 2026 22:15:54 +0200 https://doi.org/10.5194/ejm-38-347-2026 https://doi.org/10.5194/ejm-38-347-2026 <b>IMA Commission on New Minerals, Nomenclature and Classification (CNMNC) – Newsletter 91</b><br> Ferdinando Bosi, Frédéric Hatert, Marco Pasero, and Stuart J. Mills<br> Eur. J. Mineral., 38, 347–352, https://doi.org/10.5194/ejm-38-347-2026, 2026<br> Fri, 19 Jun 2026 22:15:54 +0200 https://doi.org/10.5194/ejm-38-337-2026 https://doi.org/10.5194/ejm-38-337-2026 <b>Piilonenite-(Nd), NaNd(CO3)2 ⋅ 3H2O, a new neodymium-dominant carbonate mineral from Mont Saint-Hilaire, Quebec, Canada</b><br> Inna Lykova, Ralph Rowe, Simon J. Teat, Glenn Poirier, and Stephanie Barnes<br> Eur. J. Mineral., 38, 337–345, https://doi.org/10.5194/ejm-38-337-2026, 2026<br> The paper is on the new mineral species piilonenite-(Nd), a new Nd-dominate carbonate with no closely related minerals or synthetic compounds from Mont Saint-Hillarie, Canada. Fri, 19 Jun 2026 22:15:54 +0200 https://doi.org/10.5194/ejm-38-325-2026 https://doi.org/10.5194/ejm-38-325-2026 <b>Argentotennantite-(Fe), Ag6(Cu4Fe2)As4S13, a new member of the tetrahedrite group from the San Genaro mine, Peru: occurrence and crystal structure</b><br> Jiří Sejkora, Dalibor Velebil, Cristian Biagioni, Zdeněk Dolníček, and Jaroslav Hyršl<br> Eur. J. Mineral., 38, 325–336, https://doi.org/10.5194/ejm-38-325-2026, 2026<br> Argentotennantite-(Fe), ideally Ag6(Cu4Fe2)As4S13, is a new member of the tetrahedrite group found in the San Genaro mine, Castrovirreyna Province, Huancavelica, Peru. It occurs as anhedral grains up to 100 μm in size, or, more commonly, it forms micrometer-sized rims around crystals of argentotetrahedrite-(Zn) or replaces the latter around cavities and fissures, along with Ag-rich tennantite-(Fe). It is cubic, I3m, with a = 10.4365(5) Å, V = 1136.75(17) Å3. Thu, 11 Jun 2026 22:15:54 +0200 https://doi.org/10.5194/ejm-38-305-2026 https://doi.org/10.5194/ejm-38-305-2026 <b>Formation of black opal in the pegmatites from Volyn (Ukraine) – an example for interaction of silica with organic matter</b><br> Gerhard Franz, Vladimir Khomenko, Vsevolod Chornousenko, Armin Zeh, Ferry Schiperski, Simon Gouzy, Ulrich Gernert, and Jörg Nissen<br> Eur. J. Mineral., 38, 305–324, https://doi.org/10.5194/ejm-38-305-2026, 2026<br> Black opal, a rare amorphous SiO2 variety, results from the interaction of silica with organic matter and therefore hints at traces of life, including the early Earth and Mars. The Volyn occurrence is one of the few examples of black opal worldwide and is the unique case of a pegmatitic occurrence in a granite; its age is at least 200 Ma. The structure consists of micrometer-large sphere-like arrangements of nano-sized grains and shows shape relicts of fossils, known from Volyn as "kerite". Fri, 22 May 2026 22:15:54 +0200 https://doi.org/10.5194/ejm-38-281-2026 https://doi.org/10.5194/ejm-38-281-2026 <b>Mineralogy of sulfide mineralization from the world-class Li–Sn–W Cínovec greisen-type deposit, Bohemian Massif, Czech Republic</b><br> Ondřej Krátký, Jan Cempírek, Sebastián Hreus, Luboš Vrtiška, Jiří Sejkora, Zdeněk Dolníček, Jakub Výravský, Radek Škoda, Karel Breiter, and Vojtěch Šešulka<br> Eur. J. Mineral., 38, 281–304, https://doi.org/10.5194/ejm-38-281-2026, 2026<br> Mineralogical, paragenetic, and geochemical data on sulfidic mineralization from the Cínovec greisen-type deposit show that distribution of sulfides is irregular and not strictly bound to prevalent Li–Sn–W mineralization. Progressive development of metal contents in the reduced sulfide-bearing hydrothermal fluid proceeds from Zn–Cu–Sn to Pb–Bi–Ag and As–Sb. Late-stage sulfate- and fluorine-bearing fluids partly altered earlier mineralization but did not deposit significant ore content. Wed, 20 May 2026 22:15:54 +0200 https://doi.org/10.5194/ejm-38-263-2026 https://doi.org/10.5194/ejm-38-263-2026 <b>Retrograde crystallization of clay minerals in metamorphic rocks linked to fluid circulation related to fault activity</b><br> Isabel Abad, Matías Reolid, Juan Jiménez-Millán, and Fernando Nieto<br> Eur. J. Mineral., 38, 263–280, https://doi.org/10.5194/ejm-38-263-2026, 2026<br> Metamorphic rocks affected by a fault have undergone chemical, mineralogical, and textural changes. The most significant is the enrichment in clay minerals (chlorite, kaolinite, and smectite). Geothermometry of the new chlorites made it possible to determine the temperatures of the processes (predominantly < 225°C), promoted by the fault dynamics (mainly fluid-related alterations). The retrograde alteration also affected the fluid-accessible zones of the original rocks, with growth of the same clay minerals. Mon, 11 May 2026 22:15:54 +0200