Götzenite and wöhlerite were found as part of a fissure assemblage in the Fohberg phonolite (Kaiserstuhl, SW Germany) in close contact to each other. Götzenite shows rotation twinning on [001], and wöhlerite shows reflection twinning on (100). Götzenite represents a special case, where the twin domains are arranged in a certain way with the main axis n_x of the optical indicatrix being parallel to the twin axis c in both domains.

Loparite is a chemically complex perovskite oxide; the crystals often show zoning and develop as spinel-type interpenetration twins. Atomic-scale analyses of a sector-zoned twin from Mt Khibiny have revealed that cubic and octahedral sectors exhibit distinct elemental ordering, driven by differences in composition and slow cooling. The configuration of twin boundary contacts indicates twinning by nucleation, followed by independent growth of the domains in twin orientation from the melt. 

Two new minerals, zhenruite, ideally (MoO₃)₂·H₂O, and tianhuixinite, ideally (MoO₃)₃·H₂O, are described. Zhenruite is monoclinic with space group P2₁/m and unit-cell parameters a = 9.6790(6), b = 3.70653(19), c = 7.1029(4) Å, β = 102.391(5)°, V = 248.89(2) ų, and Z =2. Tianhuixinite is hexagonal with space group P6₃/m and unit-cell parameters a = 10.5963(12), c = 3.7216(4) Å, V = 361.88(9) ų, and Z =2. 

Spaltiite, ideally Tl₂Cu₂As₂S₅ (Z = 4), is a new thallium sulfosalt mineral discovered at the renowned Lengenbach locality in the Binn Valley, Canton of Valais, Switzerland. Spaltiite is a distinctly layered structure, with alternation of polar As–Cu layers and two somewhat different types of thallium layers.

This study examines how trace elements are distributed between melt and crystals during dacite crystallization (675–775 °C, 200 MPa) using a two-step experiment combining long-duration runs and a mineral trap technique. Residual melts were effectively separated and analysed. LA-ICP-MS (laser ablation inductively coupled plasma mass spectroscopy) data for elements like P, Y, Zr, Nb, Cs, Ce, Yb, and U reveal that, while Cs and U stay incompatible, other elements are affected by the type of crystallizing minerals.

Keutschite, Cu₂AgAsS₄, is a new mineral from the Uchucchacua polymetallic deposit, Oyon District, Catajambo, Lima Department, Peru. The ideal formula, derived from the crystal structure, is Cu₂AgAsS_4. The name honours Frank Keutsch (Harvard University), a German chemist who first drew attention to the mineral during his study of the minerals of the alabandite zone of the Uchucchacua deposit.

We conducted this research to gain an understanding of the unknown crystal structure of mineral launayite, which contains elements like antimony, copper, and lead. Using advanced X-ray techniques, we solved its crystal structure and discovered new details, such as unit cell parameters, symmetry, and substitutions. These findings provide accurate information about its relationship with rouxelite.

This study compares trace elements with the Spruce Pine pegmatite deposits in the United States and the pegmatite deposits in East Qinling in China to explore which types of deposits have the potential to become high-purity quartz raw material deposits. In addition, we also carried out technical purification and economic evaluation of the collected samples, aiming to provide guidance on technical purification and trace element determination of high-purity quartz deposits.

Åsgruvanite-(Ce) is a new rare Earth element (REE) mineral from Åsgruvan in Västmanland, Sweden, linked to Bastnäs-type mineralisation. The chemical formula ideally includes cerium, aluminium, silicon, arsenic, carbonate groups, chlorine, and fluorine. The mineral forms small, grey-green, lustrous grains with distinct cleavage and high density and is associated with carbonates and REE minerals like gadolinite and an allanite-like mineral. It has a unique layered crystal structure.

We report a new ultra-high-pressure (UHP) locality in the western Alps (Italy). Micro-Raman analyses of garnet-hosted inclusions reveal the metamorphic evolution from the prograde path to exhumation. The finding of coesite in the Internal Piedmont Zone (IPZ) meta-ophiolites of Orco Valley suggests that UHP localities represent remnants of a former level that underwent comparable conditions in the coesite stability field in the oceanic slab, from Lago di Cignana to Monviso Massif.

Orthopyroxenes are important rock-forming minerals. They are solid solutions mainly between an Mg and a Fe endmember. Their thermodynamic properties are needed to model the P–T–X paths of igneous and metamorphic rocks. Samples along this Fe–Mg binary were synthesized at 800 °C/1.5 GPa, and their heat capacity was measured using calorimetric methods. From these data, the entropies along the solid solution could be derived, and it was found that this solution behaves thermodynamically ideally.

We conducted experimental and computational studies, compiling datasets of compounds with established refractive indices and supplementing them with our measurements of compounds containing I⁻, Br⁻, or Br⁷⁺. We calculated the electronic polarizabilities of these ions to estimate the mean refractive index of I- and Br-containing compounds. Results were compared to the Gladstone–Dale approach, confirming their reliability in predicting optical properties.

Synthetic lepidolites and Li-muscovites have been investigated using two-dimensional cross-polarisation heteronuclear correlation magic-angle-spinning solid-state nuclear magnetic resonance spectroscopic experiments. All results show a related ordering of the tetrahedral and octahedral sheets, with more tetrahedral Al sites close to Al-rich octahedral sites preferably coordinated by OH^- anions and Si-rich tetrahedral regions close to Li-rich octahedral sites preferably coordinated by F^- anions.