Zr-bearing accessory minerals in granites from Scotland and Northern Ireland, UK, have been examined with a scanning electron microscope and their compositions analyzed by electron microprobe. Four types of zircon were identified: magmatic, late-stage magmatic, and two hydrothermal types. Baddeleyite, dalyite, zirconolite, a eudialyte-group mineral, probable lemoynite, and Zr-bearing aegirine were also identified. These accessory minerals are used to help define the magmatic environment.

We sampled pyroclastic fallout deposits from Hungary and from New Zealand in order to get the original water content of the quartz crystals. Our main results imply no significant change in water content of the quartz phenocrysts. All sampled crystal populations contain identical water contents in case of both the Bükk Foreland and the Kaharoa eruption. Thus, there may have been similar physicochemical conditions in the magmatic system just before the eruption.

We examined the experimental deformation and phase transition of a bridgmanite analogue, NaCoF₃, using a resistive-heated diamond anvil cell and a synchrotron radiation source. We wanted to observe the behavior of NaCoF₃ under uniaxial compression and its plastic properties, as well as to determine if it is a suitable analogue for natural samples. We observe 100 and 001 compression textures and link those to the dominant deformation mechanism in the perovskite structure.

We found Ca- and S-rich rhabdophane in the upper part of the oxidation zone of a sulfide occurrence, where it forms spherules up to 35 µm in size and aggregates in fractures in goethite. Its formation is probably associated with desorption of REEs from Fe³⁺ oxyhydroxides and clay minerals in the oxidation zone and the influx of P from the soil as well as from the precursor rocks. The enrichment with REE phosphate in the studied case is similar to that in REE regolith-hosted deposits.

In this paper we calibrate a new empirical clinopyroxene-only thermobarometer based on new models. The new models show satisfying performance in both calibration and the test dataset compared with previous thermobarometers. Our new thermobarometer has been tested on natural clinopyroxenes in the Icelandic eruptions. The results show good agreement with experiments. Hence, it can be widely used to elucidate magma storage conditions.

Interpretation of vibrational spectra of serpentines is complexified by the common occurrence of divalent and trivalent cationic impurities at tetrahedral and octahedral sites. We theoretically investigate the effect of Fe and Al on the vibrational properties of lizardite, focusing on the OH stretching modes. The results allow us to disentangle the specific effects related to the valence and coordination states of the impurities, supporting a detailed interpretation of the experimental spectra.