This work presents an in-depth description of a new design for a high-temperature gas-mixing furnace using a mixture of CO–CO₂–SO₂. It has been designed and built with user safety in mind. The furnace can sustain temperatures of up to 1650 °C. This furnace sets itself apart with its size and unique quench mechanism. Crucially, the apparatus has the ability to change the gas mixture during an experiment. This feature allows the user to simulate natural environments, such as volcanoes.

Pyrite crystals with rhombohedral morphology have been known for a long time and were considered up to now as curiosities. The morphological study of well-crystallized, centimeter-sized crystals, often twinned, from the Madan Pb–Zn ore field permitted us to define such a pyrite variety as a pseudo-cubic trigonal derivative of pyrite.

The first occurrence of centimeter-thick PS-15 polygonal serpentine veins from ultramafics of Monte Avic, Val d'Aosta, is here reported. The combined mineralogical study led by three techniques with different resolutions has provided new analytical tools capable of recognizing the PS-15 polygonal serpentine. In particular, X-ray powder diffraction data (XRPD) and micro-Raman recognize polygonal serpentine more quickly and easily than transmission electron microscopy (TEM) but equally rigorously.

In this work we have applied the elastic geobarometry approach to a Chinese diamond in order to determine the depth of formation of an olivine-bearing diamond. Together with the temperature of residence at which the diamond resided in the mantle, we were able to discover that the diamond was formed at about 190 km depth. Beyond the geological meaning of our results, this work could be a reference paper for future works on Chinese diamonds using elastic geobarometry.

Paramontroseite is a V dioxide (a = 4.8960(14) Å, b = 9.395(3) Å, c = 2.9163(5) Å, V = 134.14(6) ų; space group Pbnm). The sample under investigation (Prachovice mine, Czech Republic) bears 20 wt % of Fe₂O₃, and the Fe atoms occupy tetrahedral sites arranged in the empty channel along z. Thermal expansion is anisotropic. At T > 350 °C, paramontroseite decomposes and two new phases form: V₂O₅ (V-pentoxide) and V₄Fe₂O₁₃ (Fe-tetrapolyvanadate).

We proposed a new non-destructive mineralogical methodology on sub-millimeter grains that allows us to quantify the hematite and goethite content and hematite / goethite ratio of grains prior to (U–Th) / He geochronological analysis. (U–Th) / He data performed on different aliquots with different acquisition times show no remarkable differences in age, opening a new way to investigate the (U–Th) / He data evolution in supergene lateritic duricrusts.

The diversity of chemical patterns in multi-stage fluorite mineralization from two neighbouring deposits in the Black Forest is investigated. From over 70 samples, 7 fluorite groups and 3 hydrothermal events are identified after chemical and mathematical classification. The relative chronology and features suggest different mineralization histories and source aquifers for both deposits despite their proximity. Genetic differences are likely controlled by different behaviours of their host rocks.

There are unresolved problems related to the nomenclature and identification of mineral species belonging to the triphylite group of minerals. They can be solved by discarding the traditional views on succession of mineral species during oxidation. In other words, it is necessary to separate the concepts of the origin of the mineral and the boundaries of the species.