A thorough multimethod characterisation of the green dolomite sampled at the Malentrata magnesite mine has been carried out. We observed (1) a peculiar reduction of the cell volume and (2) the origin of the peculiar green colour, mainly determined by the Fe electronic transitions, probably in combination with those of Cr. In fact, the green dolomite of Malentrata contains aliquots of a number of environmentally relevant elements, in particular Mn, Cr, and Ni.

An unusual tourmaline was studied using a multi-analytical approach. The sample comes from a granitic pegmatite on the island of Elba and consists of three generations of tourmaline: green prismatic tourmaline, a dark fibrous cap, and colourless acicular single crystals. The most likely scenario for its formation involves the miarolitic cavity fracturing due to mechanical shock, the subsequent circulation of the highly reactive cavity fluids, and the leaching of accessory biotite in the surrounding pegmatite.

Ardennite is a rare Mn-rich aluminosilicate that was originally described in Salmchâteau, Belgium. In the last few years, new samples of ardennites have been found at several localities close to Salmchâteau. These samples were analysed by electron microprobe, single-crystal X-ray diffraction, and infrared spectroscopy. The results given in this paper allow us to identify the main substitution mechanisms that occur in Belgian ardennites and to discuss the nomenclature of the ardennite group.

The structure of beryl has been a topic of research for decades but is still not entirely understood. This especially applies to substitutions by Fe ions and the occupation of the channels of beryl by H₂O and alkalis. The growing amount of studies makes it difficult to gain an overview on these topics. Therefore, this article reviews the current consensus and debates found in the literature.

To explore the compositional constraints on Cl incorporation into amphiboles, which can be used to characterize transient brines, amphiboles were synthesized with a broad range of Cl concentrations. Amphibole Cl was found to be dependent on the Fe^2+,3+ content, but not the tetrahedral Al content or K / Na ratio. Cl incorporation was found to contract the unit cell along a and expand it along b and c. Molar volumes were derived for endmember Cl-amphiboles using multivariate regressions.