The unusual mineralization with willemite, rare Cu arsenides (koutekite, kutinaite) and balkanite was found at a sample originating from the Jerusalém deposit (shaft No. 9), Příbram uranium and base-metal ore district (Czech Republic). The gangue is formed by earlier siderite and quartz intensively replaced by abundant willemite and younger dolomite group minerals with hematite inclusions and the youngest calcite. The ore mineralization represented by sphalerite, djurleite, anilite, covellite, stromeyerite, balkanite, koutekite, kutinaite, primary anglesite and Hg-rich silver is accompanied by Zn-rich hisingerite, baileychlore and Fe-oxides with variable but significant Si contents. The detailed description and quantitative chemical data for individual mineral phases are given. The studied mineralization was formed in significantly changing redox conditions (from reducing to highly oxidizing) with a distinct decrease of temperature (down to below 70(3) °C).

Rare sulphate of nickel, retgersite, was identified on the one specimen collected on the dump of the Lill shaft, Březové Hory ore district, Příbram (Czech Republic) in 1990s. The specimen consists of quartz gangue with dominant millerite and sphalerite. Retgersite forms light blue to blue-green curved fibrous microcrystalline aggregates up to 2 mm in size with vitreous lustre, growing on the surface and in small outer vugs of the supergene altered gangue. Retgersite was identified by PXRD and its refined unit-cell parameters (for the tetragonal space group P41212) are: a 6.7838(2) Å, c 18.2951(8) Å and V 841.94(4) Å3. Results of semiquantitative chemical analysis (EDS) as well as vibrational spectra (Raman, infrared) including their tentative assignments are also given. The studied retgersite was formed by (sub)recent weathering of primary nickel mineralisation (mostly millerite) in the mine dump conditions.

Two types of hydrothermal veins were found in the Ordovician claystones of the Bohdalec Formation (Barrandian, Prague Basin) during the excavation of tunnel of subway Line D at Prague-Pankrác site. The first type is represented by short hair-thin veinlets of various directions fulfilled by dickite. The second type comprises thicker NNW - SSE trending veins with prevailing quartz, which cut the host rocks across the whole width of the gallery. In addition to quartz, they contain also dickite, chlorite (thuringite-chamosite), carbonates of dolomite-ankerite series (Dol37.5-44.0Ank42.0-46.8Ktn10.9-16.1), calcite, fluorapatite, pyrite (with up to 0.5 wt. % Mn), galena (with ~0.6 wt. % Se) and sphalerite (with ~1 wt. % Fe and up to 0.35 wt. % Sn and 0.36 wt. % Cu). Except for calcite, which forms younger veinlets in older quartz fill, all other mentioned minerals form minute inclusions enclosed in quartz, which are arranged parallel with outer margin of the vein. Based on mineral assemblage and chemical composition of individual minerals, highly variable crystallization temperatures (<100 - 350 °C) can be interpreted in various mineralogically distinct domains of the quartz vein. We assume a polyphase, episodic origin of individual domains of the vein fill, close to the crack-seal mechanism, which was bound to successive evolution of the adjacent fault structure. The maximum formation temperatures exceeding by a value of ca. 100 °C the highest reported temperatures of Variscan thermal overprint of Lower Paleozoic rocks of the Prague Basin are explained by production of friction heat in the fault structure. It is probable that part of parent fluids originated from sedimentary iron ores occurring in the host Ordovician sedimentary sequence.

The new occurrence of well-crystalline Al-hydroxide, nordstrandite, was found in the Richter quarry in Hammerunterwiesenthal (Germany). Nordstrandite forms a cluster of pink-orange elongated translucent lanceolate crystals of 6 × 3 mm in size. Nordstrandite is triclinic, space group P-1 with following unit-cell parameters: a 5.111(9), b 5.079(9), c 5.132(8) Å, α 70.3(1)°, β 74.1(9)°, γ 58.5(9)° and V 106.2(4) Å. Raman spectrum agrees very well with published data for this mineral phase and is considerably different from Raman spectra of another Al(OH)3 polymorphs. Nordstrandite was found in the close association with natrolite

A very rare phosphate collinsite was found on historical samples of chamosite from the abandoned iron mine Nučice near Prague, Central Bohemia (Czech Republic) located in Ordovician sediments of the Barrandian area. Collinsite forms white to beige radial aggregates up to 15 mm in size composed by platy crystals with pearly lustre. Its chemical composition corresponds to empirical formula: (Ca1.87Sr0.12Ba0.01)Σ2.00(Mg0.57Fe0.41Al0.01)Σ0.99 (PO4)2.00·2H2O (Sr-rich zones) and (Ca1.98Sr0.01)Σ1.99(Mg0.58Fe0.40Al0.01)Σ0.99(PO4)2.00·2H2O (Sr-poor zones). Collinsite is triclinic, space group P-1, unit-cell parameters refined from X-ray powder diffraction data are a 5.734(3), b 6.779(3), c 5.441(2) Å, α 97.33(4)°, β 108.52(3)°, γ 107.25(3)° and V 185.7(1) Å3. Collinsite was found in association with siderite in fissures of chamosite iron ore.