More than 2000 outcrops of igneous mafic rocks with ages spanning the Triassic to Cretaceous are widespread in the internal and external zones of the Betic Cordillera. This magmatism originated by continental rifting is of great interest as a potential resource for Ni, Cu and Co. However, to date, the sulfide mineralogy of these metals is still unknown.

This paper provides new data on the thermal expansion of the mineral monticellite. Although thermal expansion was already reported in 1978, the data are scant and do not allow us to compare with the new data on olivine, a common mineral. We chose monticellite because it is a mineral slag formed in a blast and ladle furnace, with refractory properties. Moreover, its behaviour matters in predicting the conditions in which a rock was formed.

Fluormacraeite is the first type mineral to be described from the Plößberg pegmatite, Upper Palatinate, Bavaria, Germany. The crystal structure of fluormacraeite has been refined using synchrotron data that has resolved a small monoclinic distortion due to ordering of K and H₂O. The general crystal–chemical properties of the monoclinic paulkerrite-group minerals are discussed.

This study evaluated quartz vein ore from the Peshawar Basin, Pakistan, for producing high-purity quartz sand. Samples were purified and the analysis revealed fluid inclusions as main impurities. Post-purification, the quartz sand showed minimal inclusions and high SiO₂ content (99.997–99.999 wt %). Impurity elements like Li and Al were significantly reduced. The refined quartz sands are deemed suitable for high-purity quartz products used in industrial applications.

The Earth recycles water and other elements in a vast system that involves the oceans, minerals, magma, and the atmosphere. We studied the part of the system that involves minerals, specifically, lawsonite and epidote because they contain both water and iron. Iron in these minerals is usually assumed to be Fe³⁺, but we discovered an unexpected amount of Fe²⁺. Reactions involving different states of Fe and water in minerals affect many processes related to element cycling in the Earth.

The nolanite supergroup has been established and approved by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association. It contains eight mineral species with the nolanite-type structure. The nolanite supergroup is subdivided into three groups (nolanite, kamiokite, and rinmanite groups). After significant changes, the classification of the nolanite supergroup was approved again.

Tungsten (W) concentrations in fluids in equilibrium with crystalline tungsten oxide are used to improve constraints of thermodynamic parameters for W solubility. W species in the hydrothermal fluids are further characterized by X-ray spectroscopy. Improved thermodynamic properties for a set of W fluid species are provided that cover a wide range of fluid compositions, necessary for understanding and describing the complex processes of W enrichment and mineralization in hydrothermal systems.

Many chemical elements occur in rocks, in ore deposits, and in the environment in trace amounts. One of them is the element tungsten. It is not clear, however, where the trace amounts of tungsten reside and how they move around. In this work, we found that the element tungsten can be carried by a common iron oxide mineral, hematite. It can be transported in hematite and released under appropriate conditions, for example in reducing environments.

The amorphous phase of the natural mineral olivine was synthesized to investigate its mechanical properties. Tensile tests with in situ optical microscopy revealed brittle behaviour of amorphous olivine. Using digital image correlation, we estimated the intrinsic strength of amorphous olivine to be about 1.8 GPa. The measured intrinsic strength of amorphous olivine should help to better identify the “weak link” that initiates or promotes macroscopic material failure.

Heimaeyite (Na₃Al(SO₄)₃) has been found in fumaroles on Eldfell volcano, which lies on the island of Heimaey, Iceland. Its crystal structure contains Al–sulfate chains and belongs to a known structure type that also comprises K–Nb, K–Ta, Na–V, and Na–Fe representatives. We registered small Fe–Al substitution in heimaeyite, which might indicate a solid solution between Na–Al and Na–Fe compounds. We investigated the specimen with electron microscopy, an electron microprobe, and X-ray diffraction.

Andreybulakhite, ideally Ni(C₂O₄) · 2H₂O, is a new oxalate mineral, which was discovered on the Kola Peninsula, Russia. Andreybulakhite forms segregations of crystals up to 2 × 1 × 1 mm in size disseminated within the fruiting bodies of Lecanora cf. polytropa lichen, whose colonies overgrow the oxidized surfaces of pyrrhotite–pentlandite–chalcopyrite ore. Andreybulakhite is named in honour of Andrey Glebovich Bulakh of Saint Petersburg State University.

In this work, we used Fourier-transform infrared (FTIR) spectroscopy to analyse 25 rubies and sapphires, including natural, synthetic, and treated specimens. By optimising sample positioning, we identified distinct spectral fingerprints for each type and treatment. This systematic approach enhances gemstone identification accuracy and contributes valuable data to existing gemological databases, enabling faster and more reliable analyses in the future.

Dacostaite is a new fluoride–arsenate mineral found in the Sb(Au) deposit of the Cetine di Cotorniano Mine (Tuscany, Italy). It shows a novel crystal structure formed by heteropolyhedral layers and isolated Mg(H₂O)₆ groups connected by H bonds. The heteropolyhedral layers are similar to those occurring in alunite-supergroup minerals, and this is a further example of the ability of nature to use similar modules in forming the large number of currently known structural arrangements. 

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.