Microscopic Interest Points from Podhorní Vrch

The prestigious European journal Mineralogical Magazine has accepted for publication a paper by a research team from Palacký University Olomouc, VŠB-Technical University of Ostrava, and the Czech Geological Survey. The study focuses on accessory minerals within coarse-grained xenoliths in the volcanics of Podhorní vrch near Mariánské Lázně.

The iron-barium silicate andrémeyerite forms skeletal crystals reaching sizes of up to 200 × 80 micrometers. Until now, this mineral was known from only a single natural occurrence at the Nyiragongo volcano in the Democratic Republic of the Congo, making Podhorní vrch the second locality in the world.Minerals of the aenigmatite-wilkinsonite series are present as short prismatic crystals. These are Na, Fe, and Ti silicates with varying proportions of iron and titanium. Wilkinsonite is also a globally rare mineral; the Mindat database lists its occurrence at only five other localities worldwide.From the pyrochlore group, the complex niobium oxides oxycalciopyrochlor and oxynatropyrochlor were identified. The latter has not yet been precisely described as a mineral species in scientific literature. These minerals form very small crystals, not exceeding 15 micrometers in size.Of particular interest are the minerals formed by the alteration of fluorapatite during the late stages of the magmatic process. In the outer parts of its crystals, calcium ions were replaced by strontium ions, leading to the formation of the rare minerals fluorkaphite, fluorsigaiite, and another previously unknown Ca-Sr phosphate.The total number of mineral species known from Podhorní vrch has thus reached forty (www.mindat.org).

Article link Jirasek, Jakub; Matýsek, Dalibor; Pour, Ondřej; Laufek, František (2026) Andrémeyerite, wilkinsonite, and other accessory minerals occurring in a residual melt derived from ijolite- and melilitolite-forming magma from the Cenozoic Podhorní vrch Hill volcano (Czechia). Mineralogical Magazine, 1-21, doi:10.1180/mgm.2026.10210.