Dear American Mineralogist Readers, Below are the Paper Highlights for this month’s issue of the American Mineralogist: International Journal of Earth and Planetary Materials. You may also view the American Mineralogist Paper Highlights list at https://msaweb.org/MSA/AmMin/ and click the “Editor’s Notes” tab, which will be available shortly after the issue is live. The DOI links below will take you to the abstract on GeoScienceWorld. If you have “IP” access via your institution’s library, it should reveal the whole paper. Consult your institution’s IT department or friendly librarian. If you have an MSA membership, authenticate your login from the American Mineralogist website at http://www.msapubs.org/. On the portal page, click the American Mineralogist link and enter your username (e-mail address) and your password (membership number). Then, search for the paper you want to read via your browser's search tools. (On most PCs, it is control-F, but that may vary for you.) Note that on GSW, you can sign up for a table of contents to be sent to you when the issue is live -- this feature is available to anyone who registers on the site. Thank you for reading American Mineralogist. Sincerely, Paul Tomascak Fabrizio Nestola Editors, American Mineralogist American Mineralogist Volume 111; Number 3; 03-01-2026 Kimberlite emplacement conditions through experimentally produced reaction rims on ilmenite macrocrysts Lydia Fairhurst, Yana Fedortchouk, Michael Powell This study explores mineral-melt reaction textures formed on mantle-derived ilmenite in kimberlite magmas, offering insights into kimberlite crystallization and magma evolution during ascent. By reproducing textures found in nature through experiments, Fairhurst et al. provide constraints on the conditions and processes shaping these reactions. These findings have broader implications for understanding similar textures in other igneous and metamorphic systems. https://doi.org/10.2138/am-2024-9608 How fluids control beryllium mineralization in a magmatic-hydrothermal system: Evidence from mica geochemistry and quartz-beryl O isotopes Haoran Wu, Hao Yang, Yusheng Zhu, Wenchun Ge, Zheng Ji, Yan Jing, Zhichao Zhang Wu et al. present mica geochemistry and quartz-beryl O isotopes, as well as zircon U-Pb ages and O-Hf isotopes, cassiterite U-Pb ages and whole-rock geochemistry for two distinct types of Be deposits (i.e., the Nasigatu greisen-type and the Zhujiayingzi quartz vein-type) in the southern Great Xing'an Range (SGXR), NE China. Nasigatu alkali feldspar granites (AG) and greisens (144–139 Ma) are nearly coeval with the Zhujiayingzi quartz veins (149–147 Ma). The collected data suggest that Be mineralization could hardly be achieved through partial melting, fractional crystallization, and/or fluid exsolution processes. Deep magmatic fluids exsolved from large deep silicic magmatic reservoirs not only provide heat and promote fluid-mineral interaction, but also efficiently extract and transport Be enriched in deep crystal mushes at varying depths. Elemental and isotopic compositions of muscovites track formation and breakdown of Be-F complexes, which served as the primary migration vehicle in the fluid system. https://doi.org/10.2138/am-2024-9678 Molecular-level insights into mechanisms of Li enrichment and occurrence in natural clay-bauxite Song Yan, Wei Li, Yuanfeng Cai, Yuli Yuan, Qisong Zou, Jinsong Wang, Xiaoke Zhang, Zhou Fang, He Zhang, Tao Sun, Weiwei Li, Jinhai Yu This study is grounded in molecular-level insights and the inter-mineral lattice evolution of lithium (Li)-bearing minerals in Li-clay deposits. Yan et al. employ a combination of microscopic morphological observations and chemical analyses using scanning and transmission electron microscopy equipped with energy-dispersive X-ray spectroscopy, as well as time-of-flight secondary ion mass spectrometry and other spectroscopic techniques, to investigate the occurrence of Li. These findings reveal a hydroxyl-mediated structural response to Li enrichment, identify Li as occurring in six-coordinated and inner-sphere complexed forms, and indicate a transformation from di-octahedral to tri-octahedral configurations. The authors elucidate the mechanism of Li enrichment within pseudo-hexagonal cavities and clarify the inheritance relationships of Li-bearing structures among different minerals. Based on these findings, Yan et al. propose a roasting-free and more ecologically friendly solution for Li extraction. https://doi.org/10.2138/am-2024-9683 Genesis of jordanite-geocronite solid solution series in the Huize Pb-Zn deposit, SW China: Implications for fluid evolution in the late mineralization stage Songning Meng, Yu-Miao Meng, Xiao-Wen Huang, Xiangping Gu, Zeming Shi, Rui-Zhong Hu, Xian-Wu Bi This study presents the systematic mineralogical investigations of the newly identified jordanite-geocronite solid solution (JGSS) series in the Huize Pb-Zn deposit. The occurrence of JGSS indicates significant Sb- and As enrichment in the late-stage ore-forming fluids. The formation of JGSS involves multiple fluid-mineral interactions, which are primarily controlled by temperature, fO2, and fS2. The compositional variations of late-stage sulfosalts, particularly JGSS, offer valuable insights for mineral exploration in hydrothermal systems. Studies from various deposits such as Huize (China), Coranda-Hondol (Romania), and Huachocolpa (Peru) have demonstrated that As/Sb or As/(As+Sb) ratios in JGSS exhibit systematic spatial patterns, typically decreasing from the core of ore bodies outward or from depth to surface. These zonation trends reflect the upward migration of hydrothermal fluids and can be used to trace fluid pathways, highlighting the importance of sulfosalts in understanding ore genesis and assisting mineral exploration. https://doi.org/10.2138/am-2024-9708 Infrared spectroscopy of natural Type Ib diamond: insights into the formation of Y-centers and the early aggregation of nitrogen Maxwell Day, Michael Jollands, Francesca Innocenzi, Davide Novella, Fabrizio Nestola, Martha Pamato A new routine for deconvoluting the IR spectra of Type Ib + IaA diamonds is presented in which the spectrum of Y-centers is included. Using a database of 178 diamonds, Day et al. show that this new routine results in higher-quality fits of the IR N-region and that neglecting Y-centers during deconvolution may result in erroneous N-defect concentrations and mantle residence times or temperatures. These results shed light on the potential identity of Y-centers and their behavior during annealing and N-aggregation. https://doi.org/10.2138/am-2024-9722 A Zr-Hf geothermometer for magmatic zircon: New experiments and formulation Leonid Aranovich, Alexander Borisov New experimental data on ZrO2 and HfO2 solubility in aluminosilicate melts of wide compositional range at temperature 900–1473 °C indicate nearly identical dependence of zircon and hafnon solubility on the melt composition. Based on this finding, a new Zr-Hf geothermometer equation for magmatic zircon is derived by thermodynamic processing of the experimental data. The thermometer does not rely on quantities used in other magmatic thermometers that may be difficult to constrain (e.g., melt composition). The commonly observed increase in Hf concentration from cores to margins of magmatic zircon crystals may be related to fractional crystallization of zircon. https://doi.org/10.2138/am-2024-9727 Conversion of titanite to rutile during the albitization of granitoids from the Sakar Batholith, SE Bulgaria: Experimental studies Anna Gumsley, Daniel Harlov, Rafał Juroszek, Beata Marciniak-Maliszewska, Petras Jokubauskas, Ianko Gerdjikov Titanite was converted to rutile during the albitization of granitoids in the Sakar Batholith, SE Bulgaria, and reproduced experimentally in this study. Four experiments involving fluid-aided alteration of titanite in a granitic system were conducted at 280 MPa and 600 °C. Four Na-bearing fluids (NaCl + H2O, NaF + H2O, Na2Si2O5 + H2O, and 2 M NaOH) were used; rutile was formed from titanite in experiments involving NaCl + H2O and NaF + H2O. The comparison between natural observation and the experimental results supports the premise that a NaCl + H2O fluid could have been responsible for the conversion of titanite to rutile during albitization, which further supports the role of NaCl-bearing fluids during the albitization of granitoids in general at mid- to upper-crustal pressures in the presence of alkali-bearing fluids. This implies that the geochemical relationship between rutile and titanite is more a function of the chemistry of the fluid and host rock, especially if they are Na-rich, rather than the P-T conditions. https://doi.org/10.2138/am-2024-9731 Raman spectroscopic investigation of ianthinite [U24+(UO2)4O6(OH)4(H2O)4]·5H2O, a rare mixed-valence uranium oxide hydrate Tyler Spano, Travis Olds, Addison Malone, Brodie Barth, Nicholas Kaitschuck, Jennifer Neu, Daniel Felton, Andrew Miskowiec This work demonstrates that ianthinite has significant implications for identifying alteration phases of primary uranium ores in environmental settings via vibrational spectroscopy. Spano et al. provide new insights into the correlation between the structural features of mixed-valence U minerals and the resulting Raman spectra of these materials, which have important implications for assessment of the mineralogy of the nuclear fuel cycle. https://doi.org/10.2138/am-2025-9759 Uncovering the mineral assemblages of six major gold deposit types: A machine learning approach to big data analytics of a global mineralogical database Renguang Zuo, Bin Wang, Oliver P. Kreuzer This study developed a machine learning approach to defining the characteristic mineral assemblages of the six most economically significant gold deposit types [orogenic, epithermal, porphyry, Carlin, iron oxide-copper-gold (IOCG), and volcanogenic massive sulfide (VMS)]. Zuo et al. used association rule mining with an improved Apriori algorithm that constrains the rule consequent to deposit type, on a global database of 454 gold deposits. Visualization of the rule set through bipartite and unipartite networks revealed distinct mineral-to-gold deposit relationships. This study also showed that a machine learning approach to big data analytics of a global mineralogical database can detect both known and as-of-yet-unrecognized mineral associations. As such, this approach, which links geology and big data, offers new opportunities for mineral exploration targeting and gold deposit research. https://doi.org/10.2138/am-2025-9777 Toward the continuous series of HgS-ZnS solid solutions: Zn-rich metacinnabar assemblages in the Vorontsovskoe gold deposit, Northern Urals, Russia Fedor Sandalov, Mikhail Rassomakhin, Natalia Vlasenko, Sergey Britvin, Dmitry Artemyev, Sergey Stepanov, Elena Belogub Sandalov et al. reveal that a complete series of ZnS-HgS solid solutions with a sphalerite-type structure may be found, dispelling the potential for a miscibility gap in nature. Both strongly Zn-enriched metacinnabar and Hg-enriched sphalerite crystallize from high-temperature hydrothermal fluids (>250 ºC) enriched in Tl-Cu-Zn-Hg-As-Sb-S. These phases are particularly well-developed in sulfide-sulfosalts assemblages within gold-bearing breccias of the Vorontsovskoe deposit. Notably, the authors identify Mn as a potentially structure-stabilizing impurity in metacinnabar These results may provide crucial constraints for future experimental studies of the Hg-Zn-Mn-S cubic system, development of novel hydrothermal synthesis methods for Hg1-x-yZnxMnyS compounds, and design of materials with tailored electromagnetic properties for advanced technological applications. https://doi.org/10.2138/am-2025-9783 (Li,Na)-P substitution in garnet: an indicator of ultrahigh-pressure conditions in subducted continental crust Martin Racek, Petr Jerabek, Prokop Závada, Martin Svojtka, Ondrej Lexa, Pavlina Hasalová, František Veselovský, Pavla Stipska This work demonstrates that Fe-rich garnet can incorporate minor amounts of Li, Na, and P in ultrahigh pressure rocks. The incorporation of Li follows a (Na,Li)1P1M2+-1Si-1 substitution. This observation, based on coesite-bearing metagranites from the Bohemian Massif, is valid for crustal quartzofeldspathic rocks involved in continental subduction. The results indicate that garnet is an important carrier of Li, with implications for its mantle cycle. https://doi.org/10.2138/am-2025-9836 Microstructural and chemical responses of lunar pyroxene to shock shearing under low-to-moderate shock conditions Jiawei Zhao, Xiang Zhang, Yuqing Chang, Axel Wittmann, Zhiyong Xiao, Xiang Wu, Chang Xu, Yuqi Qian, Qi He, Siyuan Zhao, Kenan Cao, Haipeng Song, Cheng Qian, Wentao Hu, Biji Luo, Zhenbing She, Fabin Pan, Long Xiao Shock shearing facilitates systematic plastic deformation, frictional melting, and pigeonite exsolution in lunar augite. The composition and structure of pyroxene are prone to being modified under low-to-moderate shock conditions. Localized melting and recrystallization processes in shocked pyroxene promote anomalous Raman peaks in spectra linked to tetrahedral cation substitutions which can be a diagnostic shock indicator. https://doi.org/10.2138/am-2025-9877