The paper describes an analysis of the crystal structures of the minerals of the triphylite, alluaudite, zwieselite, and graftonite groups, from the perspective of the ubiquitous presence of 2-polyhedra-wide ribbons formed from corner linking of M₂(PO₄)₂Φ₈ cyclic tetramers. The study helps to unify the crystal chemistry of the four most dominant primary Fe and Mn phosphate mineral groups in granitic pegmatites.

The two most recent eruptive events of Nisyros volcano (Greece) record the interaction between variably evolved magmas by the presence of mafic enclaves, indicative of multiple recharge events within the magma chamber. We use the mineral chemistry composition to constrain the location of the main eruptible reservoirs and their evolution at the transition from explosive to effusive activities, with implications for magma migration and storage in the crust.

During project STARDUST, over 5500 specimens were recovered. Among them, a micrometeorite from Oslo (NMM/L2) revealed a new Al–Cu alloy with Al₄Cu₉ stoichiometry. This phase was approved as a new mineral named jonlarsenite. The microspherule shows features typical of micrometeorites. Its extraterrestrial origin is confirmed by oxygen isotope composition and chondritic chemistry, similar to previously known Al–Cu meteoritic materials.

Calcium silicate perovskite (Ca-pv) is the third most abundant mineral in Earth's interior. Knowledge of its elasticity is significant for deciphering the origins of seismic signatures. Elasticities and sound velocities of Ca-pv have been theoretically investigated. Compositional effects on elastic properties and velocity anisotropies of Ca-pv are significant at lower-mantle pressures. Ca-pv may be related to the observed seismic anomalies associated with subducted oceanic crust in the lower mantle.

Suenoite is a new Pnma amphibole discovered in the Mn ore deposit of Scortico–Ravazzone, Apuan Alps, Tuscany, Italy. Its discovery adds further complexity to the amphibole supergroup, and it represents the first Pnma amphibole with ^BMn²⁺.

A suite of clinopyroxenes from ankaramitic magmas of the Miocene Teno massif and Roque del Conde shield volcanoes (Tenerife, Canary Islands) were studied to obtain geothermobarometric information on the anatomy of the volcano plumbing system.

Marioantofilliite, ideally [Cu₄Al₂(OH)₁₂](CO₃)•3H₂O, is a new member of the hydrotalcite supergroup occurring as a supergene mineral in the Cu–Fe deposit of Monte Copello–Reppia (Liguria, Italy). Its name honours Mario Antofilli (1920–1983) for his contribution to the knowledge of the mineralogy of Liguria. Its discovery and description improve the knowledge of layered double hydroxides (LD), with implications for the group of Cu–Al LDH actively studied for its technological properties. 

Seventeen tourmalines from Brazil were investigated by structural and chemical techniques. Most samples are Na-dominant and belong to the alkali group. They correspond to fluor-elbaites or elbaites, except one sample, which corresponds to a rossmanite. Structural data indicate that the B site is fully occupied by boron, that the T site is occupied by Si, and that the Z site is mainly occupied by Al. The X site contains vacancies, Na, K, and Ca, and the Y site is mainly occupied by Li, Al, and Fe²⁺.

Single-crystal X-ray diffraction has been used to characterise the structural properties of a CaIrO₃ orthorhombic perovskite-type structure under ambient and high pressures. It has been found that the structure of this compound is more distorted than other CaO perovskites. Structural determination at high pressure also shows a peculiar compression behaviour that is different from the other CaO perovskites. This explains why this material is much stiffer than expected.

Zircon in highly differentiated systems such as rare-metal granites often exhibits unusual texture and composition that need to be clarified. Based on a detailed study on zircon from the Beauvoir rare-metal granite (France), we show that zircon crystals were partially replaced during the magmatic–hydrothermal transition of these systems, resulting in a significant change in their crystal texture and chemistry.

The Léon region in France offers a window into the dramatic geological processes that shaped continents. Studying ancient rocks called eclogite, we uncovered a history of magma generation, deep burial and rapid crustal movement between 390 million and 300 million years ago. The area was shaped by subduction dynamics, where shifting tectonic plates stretched and compressed the crust. These findings help us understand how ancient geological processes continue to influence the Earth’s surface today.

A new rare-earth-bearing silicate is described from a manganese ore deposit in the Pyrenees. It belongs to the epidote family and is characterised by the formula Mn²⁺Ce(MgAlMn²⁺)(Si₂O₇)(SiO₄)F(OH).  This new mineral commonly contains inclusions of an Mn-rich yttrium borosilicate, a potentially new mineral of the hellandite family. This is a new type of occurrence for hellandite – while rare earths are under the spotlight.

Chromites found within the fusion crust of ordinary-chondrite meteorites display significant differences with respect to chromites found in the interior of the same meteorites. Chromites within the fusion crust, when compared to those in the interior of the meteorite, display a significantly higher Mg / (Mg + Fe) ratio; moreover, ca. 15 % of the chromites formed within the crust display small but detectable amounts of Ni.

We conducted this research to gain understanding of the mineral rouxelite, which contains elements like antimony, copper, mercury, and lead. Using advanced X-ray techniques, we re-examined its crystal structure and discovered new details, such as unit-cell parameters, symmetry, and substitutions. These findings provide accurate information about how the mineral forms and behaves. This work not only updates scientific knowledge of rouxelite but also offers insights into its chemical complexity.

This study investigates the order–disorder phase transition in ankerite samples that vary in Fe content within their crystal structure. Results indicate that both the temperature and the character of the order–disorder phase transition are significantly influenced by the amount of Fe in the mineral's crystal structure. The obtained results might have significant implications for ankerite mineral physics under non-ambient conditions and significance in geophysical modeling of the Earth's mantle.

Natrolitised Early Cretaceous metaplutonites (melteigites, ijolites) contain various accessory minerals. The natrolitisation was a very low-temperature process, which did not affect most of the primary minerals, including most of the accessories. The evidence shows the release of barium and strontium, possibly from feldspathoids, from primary Na–Ca feldspars, and optionally also from glass, during the natrolitisation.

The thermal reaction Fe²⁺ + OH^- → Fe³⁺ + O^2- + e^- + H⁺ in hydrous silicates has tremendous implications in planetary-scale phenomena like electrical anomalies, water cycling, seismicity, volcanism, and ore generation. We annealed riebeckite crystals up to 750 °C and P = 0.7 GPa and show that the amphibole stability is extended without any Fe oxidation, implying that thermally activated electron hopping contributes to the electrical conductivity of lithospheric rocks during subduction.

A thorough multimethod characterisation of the green dolomite sampled at the Malentrata magnesite mine has been carried out. We observed (1) a peculiar reduction of the cell volume and (2) the origin of the peculiar green colour, mainly determined by the Fe electronic transitions, probably in combination with those of Cr. In fact, the green dolomite of Malentrata contains aliquots of a number of environmentally relevant elements, in particular Mn, Cr, and Ni.

This study describes the elbaite neotype, found in crystals from a site on Elba island, Italy. Researchers analyzed these nearly colorless crystals and found that their formation was influenced by earlier changes in the surrounding rock. As different minerals formed first, they set the stage for elbaite to develop later in deeper spaces. This work helps us understand how changes in the local environment affect how and when certain minerals grow.

In this work, we present the most iron-rich chrysoberyl discovered to date, found in the Sabatini Volcanic Complex (Latium, Italy). We provide a comprehensive overview of its chemical, structural, spectroscopic, and optical properties. The characterization of this chrysoberyl reveals several unique features, offering valuable insights into its genetic model and geochemical constraints, which are consistent with existing literature on the Sabatini complex and with ongoing research.

Garnet crystals record the evolution of the pressure–temperature conditions during their growth. Thermodynamic modelling and the presence of coesite inclusions testifies that these rocks equilibrated along a pressure–temperature path crossing the equilibrium between quartz and coesite. This allows for discussing the role of energetic barriers during crystal growth. This was found insignificant, except for rocks that contain previous garnet crystals that have difficulties to achieve equilibrium.