This is the first description of the new mineral kahlenbergite, found in the Hatrurim Basin, Israel, which is a region with unusual pyrometamorphic rocks. Kahlenbergite is chemically and structurally characterized. It is very similar to β-alumina compounds, which are synthetic materials known for their properties as fast ion conductors. Research in the Hatrurim Basin is needed to understand the complex mechanisms that created this mineralogically diverse hotspot of new minerals.

Chapmanite is a seemingly rare mineral, a silicate of the elements iron and antimony. In this work, we evaluated how stable and how soluble this mineral is. The goal was to determine if this mineral can store the toxic element antimony. Our results show that it is possible, but its formation in nature is hindered and slow. Yet, in some special environments, it could store and keep antimony over longer time.

On the west coast of the German North Sea island of Sylt, an electrum–quartz pebble weighing 10.4 g was discovered in a cliff of Saalian glaciogenic sediments. This is an unusually large and rare precious metal to find. Within our paper we document and characterize this discovery. An attempt to investigate its provenance points towards a southern Norwegian origin. This leads to the conclusion that ice advance events were involved in transporting this pebble from Norway to Germany.

The infrared absorption spectrum of an antigorite sample, an important serpentine-group mineral, is compared to its theoretical counterpart computed at the density functional level. The model reproduces most of the observed bands, supporting their assignment to specific vibrational modes. The results provide robust interpretations of the significant differences observed between the antigorite spectrum and that of lizardite, the more symmetric serpentine variety.

Metamorphic rocks contain information about their original rocks and thus provide insight into the earlier stages of a region of interest. Here, we used the whole-rock chemical composition and stable boron isotopes of a suite of rocks from the Alps (Italy–Austria), which were deposited in a restricted intramontane basin before the Alpine orogeny. It is possible to reconstruct the depositional conditions for these sediments, which are now common metamorphic rocks such as schists and gneisses.

Unusually large lizardite (Lz) crystals from Monte Fico serpentinites, Elba (Mellini and Viti, 1994), have allowed several subsequent studies. During a µ-Raman study of serpentine minerals (Compagnoni et al., 2021), the careful microscopic examination of this Lz showed spongy microstructure. TEM observations confirmed that the Lz hosts voids, filled with chrysotile and polygonal serpentine; their mutual relationships indicate that Lz grew up with a skeletal habit and fibres epitactically.

A new locality of ardennite-(As) is described in Nežilovo, North Macedonia. This mineral grows in specific conditions, which makes it useful to reconstructing the conditions of rock formation. Phengite mica that was found also supports this investigation. This explanation results in a new proposal for mineral formula calculation of ardennite-group minerals and reviews the current ardennite-group end-members. This occurrence has developed through three metamorphic stages which are also described.

The study provides new insights into the OH stretching vibrations of serpentine species (lizardite, chrysotile, antigorite) encountered in veins of peridotite. A combination of infrared spectroscopy in the mid-infrared and near-infrared ranges and Raman spectroscopy enabled us to interpret most of the observed bands in the fundamental and first overtone regions of the spectra and to propose consistent spectral decomposition and assignment of the OH stretching bands for the serpentine species.

This paper investigates the possibility for melts to migrate within extensively deformed crystals and assesses the impact of this intracrystalline melt percolation on the chemical composition of the deformed crystal. We here document that the presence of melt within a crystal greatly enhances chemical diffusive re-equilibration between the percolating melt and the mineral and that such a process occurring at crystal scale can impact the large-scale composition of the oceanic lithosphere.

We investigated the thermal vibrations of ⁵⁷Fe atoms in the crystal structure of a high-pressure form of the oxyhydroxide compound (Al,Fe)OOH. The results of our nuclear resonant inelastic X-ray scattering experiments on single crystals show that ⁵⁷Fe atoms vibrate at different frequencies and with different amplitudes when being displaced in different directions. This anisotropy of atomic vibrations is transmitted to related thermal properties and can be described using second-rank tensors.

Glauconite and celadonite are green micas which are significant as indicators of palaeoenvironments. They share similar chemical compositions, characterized by their Fe²⁺, Fe³⁺ and Mg content despite their white-mica structure; however, the chemical and structural relations were unknown. Their rare coexistence in volcanic rocks due to bacterial activity has allowed us, after an electron microscopy study, to identify a compositional gap between them justified by structural differences.

We performed experimental measurements of elastic parameters of fayalite. The idea is to better define the effect of olivine Fe content on these parameters and test how sensitive these are when adjusting mineralogical models to seismic data. The trend of the olivine shear modulus with Fe content is well defined, but that of the bulk modulus remains less constrained, and more experiments on olivines with different Fe compositions are needed.