The CaSiO₃ system exhibits structural complexity with various polymorphs under different pressure and temperature conditions. This study stabilizes a new high-pressure polymorph, parabreyite, via multianvil syntheses at 4–5 GPa and 600–800 °C. Parabreyite's triclinic structure, with distinct threefold tetrahedral rings, was solved using 3D electron diffraction and X-ray diffraction. Elastic properties, thermal expansion and Raman spectra differences with breyite were analyzed.

The compositional variation in a multi-coloured, zoned tourmaline from the Cruzeiro pegmatite, Brazil, reflects melt chemical evolution during the entire pegmatite differentiation. In uncontaminated granitic pegmatite systems such as that of Cruzeiro, the compositional evolution of tourmaline progresses from schorl to fluor-elbaite, rather than directly from schorl to elbaite, to reflect co-enrichment in Li and F during fractional crystallization.

We examined the influence of Al₂O₃ and H₂O on the position of the coesite–stishovite transition by means of in situ X‑ray diffraction measurements with the large-volume press at the synchrotron PETRA III in Hamburg. The position of the transition was found to be shifted almost in parallel by about 1.5 GPa to lower pressures compared to results for the pure SiO₂ system by Ono et al. (2017). Stishovite of this study containing Al and H is only partially quenchable but transforms back to coesite.

Nannoniite, Al₂(OH)₅F, is a new mineral species discovered in the Cetine di Cotorniano mine (Tuscany, Italy). Its description was possible through a multi-technique approach, and its crystal structure was solved through three-dimensional electron diffraction, revealing close relations with gibbsite. The partial replacement of (OH) by F induces subtle by detectable structural changes. This study reveals that Al hydroxides could be a source of F in geological environments.

The growing interest in lithium (Li) diffusion for the determination of timescales of magmatic events increases the necessity to better understand Li diffusion in common mineral phases. In this context we analyzed Li diffusion in plagioclase, one of the most common mineral phases. Our study is the first to confirm two diffusion mechanisms for Li in plagioclase, and our results indicate timescales derived from Li diffusion data in previous studies were underestimated by a factor of up to 100.

In situ U–Th–Pb dating of allanite and monazite provides a robust record of polymetamorphism in greenschist facies metapelites in the Austroalpine Unit. Variations in bulk rock Ca, Al and Na contents produced a wide range of REE-mineral-phase relationships and microstructures, making them excellent geochronometers in complex tectonic settings. Our new pressure, temperature, time and deformation data reveal Permian metamorphism and a major crustal-scale Cretaceous detachment.

This study examines solid nano-inclusions in magnetite from the La Víbora magnesian skarn, Spain, revealing insights into mineral formation. We found two types of inclusions: representing fossilized skarn reactions and precipitated from supersaturated fluids. Nano-inclusions provide valuable clues about the Fe mineralization event, highlighting the significance of nano-inclusions in understanding geological processes and resource exploration.

Kamafugites are rare ultrabasic/basic K₂O-rich rocks. High-pressure–high-temperature experiments on four samples from the known type localities (Italy, Brazil, Uganda) constrained their melting assemblage, unlike a classical peridotite. Clinopyroxene and phlogopite are the first near-liquidus phases. Olivine appears in two runs. The different abundances of the main phases and the variable contribution of apatite, oxides and titanite explain the variegated kamafugite geochemical features.