Mining Museum Pribram

Abstract Vrančiceite is a new mineral species discovered in a sample collected from the old mine dumps of the abandoned Vrančice deposit near Příbram, central Bohemia, Czech Republic. Vrančiceite occurs as rare anhedral grains, up to 100 μm in size, in a calcite gangue, associated with cinnabar, djurleite, galena and hedyphane. Vrančiceite is black, with metallic lustre. Mohs hardness is ca. 2–3, calculated density is 6.652 g.cm–3. In reflected light, vrančiceite is light grey with a yellowish shade; bireflectance, pleochroism and anisotropy are all weak. Internal reflections were not observed. Reflectance values for the four Commission on Ore Mineralogy wavelengths of vrančiceite in air [Rmax, Rmin (%) (λ in nm)] are: 33.6, 31.2 (470); 33.9, 30.6 (546); 31.1, 30.0 (589); and 32.1, 29.1 (650). The empirical formula, based on electron-microprobe analyses, is Cu10.11(4)Ag0.01(1)Hg2.87(4)Sb0.01(1)Bi0.01(1)S7.99(8). The ideal formula is Cu10Hg3S8 (Z = 2), which requires (in wt.%) Cu 42.54, Hg 40.29 and S 17.17, total 100.00. Vrančiceite is triclinic, P$\bar{1}$, with unit-cell parameters a = 7.9681(2), b = 9.7452(3), c = 10.0710(3) Å, α = 77.759(1), β = 76.990(1), γ = 79.422(1)°, V = 737.01(4) Å3 and Z = 2. The strongest reflections of the calculated powder X-ray diffraction pattern [d, Å (I) hkl] are: 3.354 (76) $\bar{2}$01, 3.111 (68) 222, 2.833 (100) 213, 2.733 (93) 231, 2.705 (76) 2$\bar{2}$1 and 2.647 (71) $\bar{2}\bar{1}$2. According to the single-crystal X-ray diffraction data (R1 = 0.0262), the crystal structure of vrančiceite can be described as comprising Cu–S layers, connected through CuS3 polyhedra, giving rise to a three-dimensional framework with channels running along the a axis and hosting linearly coordinated Hg atoms. Structural relations with gortdrumite are discussed. Vrančiceite is named after its type locality, the Vrančice deposit near Příbram. The mineral and its name have been approved by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association (IMA2022–114).

This mineralogical and fluid inclusion study was conducted on an Au-bearing quartz–sulfide vein encountered in the deep parts of the Bytíz deposit in the Příbram uranium and base-metal district, Bohemian Massif, Czech Republic. The samples were taken where the Au-bearing vein is crosscut by the common base-metal Zn-Pb ore vein Bt23C. The early mineralization of the Au-bearing vein is composed mainly of quartz (Q-1 to Q-3), illite–muscovite, Fe-Mg chlorite, arsenopyrite, and Au-Ag alloys, showing a wide range of compositions (4–69 at. % Ag) and a decrease in Au/(Au + Ag) ratios during vein evolution. Younger hydrothermal processes led to the crystallization of nests and veinlets composed of late quartz (Q-4), carbonates (siderite, dolomite–ankerite and calcite), base-metal sulfides (galena, sphalerite, chalcopyrite, and tetrahedrite), a suite of Ag and Bi-tellurides, and acanthite. The input of Sb is manifested by the partial to complete replacement of some gold grains by aurostibite and an unnamed (Ag,Au)-Sb oxide with a composition close to AuSbO3. The fluid inclusion study, combined with chlorite thermometry and arsenopyrite thermometry, showed that the early mineralization crystallized from progressively cooled (from 300 to 400 °C down to ca. 180 °C), diluted (1.2–7.0 wt. % NaCl eq.) aqueous solutions. The late portion of the mineralization formed from aqueous fluids with highly variable salinity (0.2–23.4 wt. % NaCl eq.) and homogenization temperatures decreasing from ca. 250 °C to < 50 °C, which compare well with the base-metal mineralization of the vein Bt23C and other base-metal veins of the Příbram ore area. Our study illustrates the nature and intensity of the processes of the reworking of the early gold mineralization mediated by the younger Ag,Sb-rich base-metal fluids, giving rise to Příbram’s typical late-Variscan vein Zn-Pb mineralization.

Abstract Micro‐Raman spectroscopy was used to investigate the natural orthorhombic members (space group Pnma) along the CuSbS2–CuSbSe2 join: chalcostibite Cu1.01Sb1.00S1.99 from Dúbrava (Slovak Republic); Se‐rich chalcostibite Cu1.00(Sb0.99As0.02)Σ1.01(S1.29Se0.70)Σ1.99 and the new mineral příbramite Cu0.99(Sb1.03As0.01)Σ1.04(Se1.82S0.15)Σ1.97 both from the Příbram uranium and base‐metal district (Czech Republic). Stretching and bending vibrations of the pyramidal SbS3 groups occur between 350 and 200 cm−1; vibrations of SbSe3 groups are shifted to the range 240–80 cm−1 due to the almost twice heavier mass of Se compared with S. The shift of the ν1 symmetric Sb‐(S,Se) vibration was observed, yielding 113 cm−1, and for the ν3 antisymmetric stretching Sb‐(S,Se), vibration was about 127 cm−1. The wavenumber of the ν1 symmetric Sb–S stretching vibrations decreases with increasing Se content—from 336 (in chalcostibite) over 330 (in Se‐rich chalcostibite) to 326 cm−1 (in příbramite), and a similar situation was observed for the case of ν1 symmetric Sb–Se stretching vibrations from 220 in Se‐rich chalcostibite to 215 cm−1 in příbramite. The trend for the ν3 antisymmetric Sb‐(S,Se) stretching vibrations is the opposite, from 306 cm−1 in chalcostibite to 314 cm−1 in Se‐rich chalcostibite (Sb–S bonds) and from 180 cm−1 in Se‐rich chalcostibite to 185 cm−1 in příbramite (Sb–Se bonds). These small shifts are probably connected with the influencing of the bonding environment of SbS3 and SbSe3 pyramids. The vibrations of Cu‐S(Se) bonds are represented only by less intense bands, and the observed intense bands below 80 cm−1 should correspond to external modes.

Antimonselite from the new occurrence, Přibram uranium–base metal ore district (Central Bohemia, Czech Republic), has been studied by means of electron microprobe and X-ray diffraction. Antimonselite crystals, reaching up to 1.5 mm across, were rarely found in the calcite gangue with uraninite in association with clausthalite, tiemannite, hakite, tetrahedrite, Se-rich chalcopyrite, permingeatite, Se-rich and Se-analogue of chalcostibite and dzharkenite. Based on electron-microprobe analyses, the empirical formula of the studied antimonselite (mean of 7 point analyses, recalculated to 5 apfu) is (Sb 2.06 Cu 0.01 ) Σ2.07 (Se 2.47 S 0.46 ) ∑2.93 . The studied S-rich antimonselite is orthorhombic, the space group Pnma, with a = 11.7156(3), b = 3.9514(11), c = 11.5645(3) A, V = 535.36(15) A 3 , and Z = 4. The structure was refined from the single-crystal X-ray data to R 1 = 0.0143 for 634 reflections [with I obs > 3σ(I)]. The structure of S-rich antimonselite is isotypic to that of stibnite. Sulfur was found to be entering the selenium sites regularly without any evidence of preferential ordering of the atoms at the different sites.

The crayfish plague pathogen (Aphanomyces astaci) is one of the most important threats to indigenous European crayfish. Although it belongs among the most studied pathogens of invertebrates, only a few recent studies are available on the epidemiology of crayfish plague and its long-term effects on crayfish populations. We provide detailed data on 11 populations of European crayfish (Astacus astacus, A. leptodactylus, Austropotamobius torrentium) hit by crayfish plague in the Czech Republic between 1998 and 2011. We repeatedly surveyed the affected localities in the years following the disease outbreaks to investigate potential recovery of crayfish populations and to search for the likely sources of infection. Although the mortalities severely decimated all studied populations, European crayfish could be found in the watercourse catchments after the disease outbreaks in all but two cases. In five cases, migration barriers apparently supported crayfish survival; in two cases, the disease stopped spreading even without the presence of any barrier. Indigenous crayfish were recorded directly in the affected parts of five studied streams after some time but in most cases populations have not yet reached the original densities. Their recovery seems influenced by the population size in unaffected refuges as well as time since the outbreak. Sources of infection and transmission pathways of A. astaci apparently vary in the Czech Republic. Aphanomyces astaci of three genotype groups originating in different crayfish plague pathogen carriers were involved in the outbreaks. Direct transmission of A. astaci from invasive American crayfish present in the same stream is likely in three cases; however, these host crayfish were not recorded at the remaining localities, and long-range dispersal or other pathogen sources may be assumed. We hypothesize that chronic A. astaci infections leading to disease outbreaks under specific conditions may occur in some populations of indigenous crayfish in the Czech Republic.

ABSTRACT Although the noble crayfish (Astacus astacus L.) and stone crayfish (Austropotamobius torrentium Schr.) are critically endangered European species, their water quality requirements are not sufficiently known. This study aimed to investigate the physico‐chemical tolerance range of the noble and stone crayfish in the Czech Republic compared with those of the invasive spiny‐cheek crayfish (Orconectes limosus Raf.). At 1008 sites with crayfish either absent or present, the following 18 physico‐chemical variables were investigated: dissolved oxygen, pH, BOD5, CODCr, ammonia, ammonium ions, nitrite, nitrate ions, zinc, copper, iron, aluminium, calcium, sulphates, chlorides, total phosphorus, suspended solids, and conductivity. For the noble and stone crayfish, only minor differences in water quality were found. This indicates that the water quality requirements of these indigenous crayfish are likely to be very similar. However, significant differences in water quality were observed between locations inhabited by indigenous crayfish and those inhabited by the invasive spiny‐cheek crayfish. Based on these findings, we hypothesize that the invasive species is able to survive in locations with lower water quality. Simple logistic regression models were then used to examine relationships between the presence or absence of noble crayfish and each evaluated water quality variable. The presence of this species was related significantly with those variables that indicate nutrient enrichment (particularly ammonium, BOD5, and nitrite) and to iron. Overall, although the indigenous crayfish species were found at several sampling sites that had impaired water quality, the statistical analyses indicate that the indigenous species require water of high quality. Improvement in water quality is therefore an important step in sustaining indigenous crayfish populations. Copyright © 2012 John Wiley & Sons, Ltd.