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This study deals with petrography, geochemistry and K-Ar dating of the recently described Vimperk porphyry dyke swarm (diorite to granodiorite) and microgranite of the Milesko felsic dyke swarm described earlier in detail by Vrána (1999). The Vimperk porphyry swarm strikes N-S, and exceeds 15 km in the length. The dykes penetrate the metamorphic rocks of the Monotonous Group of Moldanubicum, small intrusions of biotite granite, and W-E trending dykes of syenite porphyry, as well (Žáček et al. 2009, Žáček et al. 2012b). The individual dykes are up to 4 km long and 2-15 m thick (Žáček et al 2012b, see Fig. 1). The Milevsko dyke swarm is more than 15 km long, and the thickness of the dykes (microgranite) is up to 10 m. The dykes with dominant N-S direction cut porphyritic amphibole-biotite melagranite (durbachite) of the Central Bohemian Plutonic Complex near its southern contact with the Moldanubian gneisses and migmatites (Vrána 1999). The studied sample Mi1 consists of a mosaic of quartz (30 vol.%), albite (25 vol.%, Ab99An1) and K-feldspar (15 vol.%), and accessory apatite, rutile and limonitized pyrite (Fig. 2e-f). Geochemically, the rock is highly evolved alkali feldspar granite. The Vimperk dykes are both significantly porphyritic and non-porphyritic with varying mineralogical composition (see Fig. 2a-d, Fig. 3a, Table 1, 2). The rocks are composed of 40-50 vol.% of normally zoned calcic plagioclase (An67-36), 5-20 vol.% of K-feldspar (Kf70-90Ab4-27Cls0-3), 5-20 vol.% of quartz, 5-35 vol.% of magnesiohornblende (Si = 7.20, Xmg = 0.71, but mostly altered to actinolite or chlorite), 5-15 vol.% of probable orthopyroxene (completely chloritized), up to 10 vol. % of brown Ti-rich biotite (3.4-4.5 wt.% TiO2, Xmg = 0.37-0.57), up to 5 vol.% of pinkish clinopyroxene and 1-5 vol.% of lath-shaped ilmenite. The accessories include fluorapatite, titanite, baddeleyite (Fig. 3b), and less abundant zircon, allanite, thorite, galena, scheelite, pyrrhotite and probable chevkinite. The secondary chlorite and actinolite can represent up to ca 35 vol.% of rock, minor are clinozoisite-epidote, secondary titanite II, albite, sagenite and calcite. Scarce miarolitic cavities are filled with quartz, chlorite, calcite and rare skeletal baddeleyite. The altered xenocrysts of plagioclase I (Fig. 2d) and rarely of K-feldspar (up to 5 vol. %) are also present along with mm-cm sized mafic inclusions (Fig. 2b). Mean magnetic susceptibility of porphyries corresponds to 0.24 × 10-3 SI, and that of felsic microgranite is 0.02 × 10-3 SI. The field gammaspectrometry of porphyries yielded the average contents of K = 3.6 %, eU = 7.1 ppm and eTh = 19.7 ppm (Table 3). The potassium is bound mainly in K-feldspar, less in biotite. Uranium and thorium are preferably bound in baddeleyite (1.96 wt.% UO2 and 0.41 wt.% ThO2), and much less in zircon (0.17 wt.% UO2 and 0.14 wt.% ThO2), see Table 3. Geochemically, the rocks of the Vimperk swarm (6 analysed samples, see Table 4), exhibit relatively varying chemical composition SiO2 (54.7-67.6 wt.%), MgO (1.0-5.0 wt.%), CaO (1.7-7.0 wt.%), and K2O (2.7-5.5 wt.%). The chemical composition ranges from basaltic andesite over trachyte to rhyolite (Fig. 4 a-f). These rocks are metaluminous to slightly peraluminous (A/CKN = 0.8-1.5), and have high-K calc-alkaline to shoshonitic character. The geochemical signatures are typical of intra-plate continental settings. The primitive mantle-normalized spider plots with Nb, Sr, Ti, and P troughs, and peaks in Th, U, and Pb, indicate an influence of crustal contamination of magma, which was generated through the partial melting of lithospheric mantle. Two samples were dated. The diorite porphyry from Vimperk dyke swarm gave an K-Ar age of 292.5 ± 9.1 Ma (1s), and the Milevsko microgranite 300.9 ± 9.1 Ma (1s). These ages are interpreted as minimal, but close to magmatic age (see Table 5). The existing data show a close geochemical relationship to mafic dyke swarms from other Moldanubian localities: from Ševětín (Vrána et al. 1993), Sušice (Vrána 2004), Kaplice (Košler et al. 2001, Vrána et al. 2005) and Štěpánovice and Hamr near Cítov (Vrána and Janoušek 2006). The contents of major elements (Fig. 4a-d) and rare earth patterns (Fig. 4e) also show a similar character as the above-mentioned dykes (Fig. 4e, cf. Vrána and Janoušek 2006). There is also significant petrographic similarity to these dykes, the major mineralogical composition, but especially the appearance of baddeleyite (Fig. 3b) and the presence of accessory galena, scheelite and other ore minerals (cf. Vrána and Janoušek 2006). The signs of Vimperk dykes, especially the occurrence of miarolitic cavities and micrographic intergrowths of quartz and K-feldspar in the matrix, indicate the rapid cooling of the magma, and the subvolcanic character of the crystallization below the surface. The temperature of ~ 752 °C, and pressure of 0.58 kbar were estimated using amphibole and plagioclase-amphibole geothermobarometers. The Vimperk swarm is situated between the Sušice dyke swarm to the west and the Ševětín dyke swarm to the east, and indicates the occurrence of similar dykes in large areas of the Moldanubicum. All these dykes are related to the late orogenic Variscan magmatism in the southern part of the Moldanubicum bound to the north-south structures connected with the Lower Permian extension tectonics of the Blanice Graben. The dykes penetrated the chilled Variscan crust shallowly below the surface in the lowest Permian and represent the last intrusive rocks. By analogy with other similar dykes of the same structural position (Vrána and Janoušek 2006), the origin of primary magma can be interpreted as a mixing of basic magma originating from the lithospheric mantle, which has been contaminated to varying degree by the acidic material of the continental crust during the uplift to the shallow levels of the Variscan crust. [ABSTRACT FROM AUTHOR]

This paper reports a unique occurrence of macroscopic ferrocolumbite in the fractionated phosphorus- and boron-rich leucogranite related to the Vydra Pluton (SW branch of Moldanubian Batholith, Klomínský et al. 2010, Žáček 2018). A small 1-2 m thick dyke of leucogranite cuts Weinsberg-type biotite granite of the Vydra Pluton (peraluminous S-type granite) at the GS117a site (49.01432° N, 13.41735°E), situated on the Czech-German border in the Šumava National Park (Fig. 1). The leucogranite consists of albite (~35 %), K-feldspar (~25 %), quartz (~30 %), minor muscovite (5-10 %), tourmaline (2-3 %), apatite (1-2 %), accessory U-rich zircon (mostly enclosed in tourmaline) and the ferrocolumbite described below (Fig. 2a-d). The leucogranite is peraluminous, A/CNK = 1.20, LaN/SmN = 2.03, Eu/Eu* = 0.33, rich in SiO2 (72.91 wt.%), Na2 O (4.55 wt.%), K2O (4.18 wt.%), and boron (~0.2-0.3 wt.% B2 O3, corresponding to ~2-3% of tourmaline in the rock), see Table 1. The high phosphorus content (0.645 wt.% P2 O5) is combined with Ca and is partially bound in apatite, with the excess phosphorus subsequently being bound in K-feldspar and albite. The leucogranite has elevated concentrations of Rb (521 ppm), Sn (86 ppm), As (64 ppm), Nb (24 ppm) and U (16 ppm), and low TiO2 (0.03 wt.%) and MgO (0.08 wt.%). It is extremely depleted in V, Cr, Ni, Sr, Ba, Y, Th (1.7 ppm) and total REE (24 ppm). The albite has elevated Rb2 O (~0.1 wt.%) and P2 O5 (up to 0.4 wt.%), and the K-feldspar contains ~0.85 wt. % P2O5 and also increased Rb2O (~0.1 wt.%). The muscovite also contains elevated Rb2O (~0.2 wt. %), Cs2 O (~0.1 wt. %), and FeOtot tot (~2.5 wt.%) (see Table 2). The tourmaline is zoned X-deficient schorl (centre) to Na-rich foitite (rim): Mg/(Mg+Fe) = 0.19-0.20, X Na = 0.46-0.58 apfu, Xvacancy = 0.39-0.53 apfu (Table 3, Fig. 3). It frequently encloses radioactive zircon rimmed by conspicuous pleochroic circles (Fig. 2c). The ferrocolumbite appeared as a unique aggregate of prismatic crystals up to 1.5 mm long, grown in the K-feldspar and plagioclase (Fig. 2d). It consists of three generations, which are well distinguishable in a BSE and by chemical composition (Figs 2d, 4, Table 4). The oldest Ta-Mn-poor ferrocolumbite I (approximately 80 % of the sample, see Fig. 2d) is enriched in W (0.04-0.05 apfu) and Ti (0.12-0.15 apfu) and has the average empirical formula (2 points): (Fe0.79Mn0.17) (Nb1.67Ta0.17Ti0.13W0.04) O6. Ta-rich ferrocolumbite II forms part of one of the prismatic crystals and irregular patches on the edge of ferrocolumbite I and has the empirical formula: (Fe0.77Mn0.20) (Nb1.31Ta0.61Ti0.07W0.02) O6. The third generation forms irregular patches on the edges of ferrocolumbite I and corresponds to Nb-rich ferrotantalite with the empirical formula: (Fe0.77Mn0.23) (Ta1.07Nb0.86Ti0.06W0.01) O6. The compositional trend of the studied ferrocolumbite-ferrotantalite is a strong increase in Ta/(Ta + Nb), slight increase in Sn and Sc, and moderate to slight decrease in Ti, W, Zr, Y, Pb and U (Fig. 4, Table 4). The leucogranite with ferrocolumbite belongs compositionally and spatially to the "Kvilda leucogranite dyke swarm" described by Žáček and Sulovský (2005) from the western vicinity of the Vydra Pluton. It represents the latest intrusions in the area - fractionated residual magma enriched in fluorine and phosphorus. The pattern is similar to highly fractionated, A-type muscovite granites enriched in Tb, Ta, Sn, F and P, e.g. Homolka, Galthof, Nakolice (Breiter and Scharbert 1995, 1998) or the dyke swarm at Lásenice (Klečka and Vaňková 1988). The occurrence of ferrocolumbite in the leucogranite explains the highly probable source of Nb found by exploration geochemistry in this part of the Moldanubian Zone in heavy mineral concentrates (Poňavič et al. 2018). [ABSTRACT FROM AUTHOR]

The clinopyroxenes from marbles and associated calc-silicate rocks from the vicinity of Výškovice, Vnarovy and Sudslavice (Prachatice District, České Budějovice Region, Czech Republic, see Fig. 1) contain up to 0.89 wt.% ZnO (~7,130 ppm Zn, 2.5 mol.% of petedunnite component), corresponding to an empirical formula of (Ca0.99Na0.01) (Mg0.74Fe0.21Zn0.024Mn0.02) (Si1.99Al0.01) O6. The marbles studied (Table 1) form lenses enclosed in biotite-sillimanite gneiss to migmatite of the Moldanubian Zone, Bohemian Massif, which underwent a polyphase metamorphic development at P = 0.4-0.8 Gpa, and T = 630-760 °C (e.g. Vrána et al. 1995). The studied marbles are composed of major calcite, while minor is clinopyroxene (Di64-87 Hd11-35, Table 2), and even less abundant are wollastonite and phlogopite with scarce plagioclase, potassium feldspar, quartz and secondary actinolite. As accessory minerals were identified fluorapatite, titanite, zircon, rutile, pyrite, galena, and sphalerite (Figs 2 and 3). Low S content 0.02 wt. % suggests that the amount of sulphide minerals is not exceeding ~0.05 %. The mineral assemblage indicates the possible formation of the petedunnite component in clinopyroxene via the following reaction (modified after Essene - Peacor 1987): 2 CaSiO3 (wollastonite) + 2 ZnS (sphalerite) + 2 SiO2 (quartz) + O2 = 2 CaZnSi2O6 (petedunnite) + S2. Analogous occurrences from various high-grade metamorphic units of the Bohemian Massif mostly contain Zn-bearing spinel as a main Zn-carrier, but in fact the Zn content in pyroxenes was mostly not determined (see e.g. Houzar - Novák 1995, Novák et al. 1997). The content of Zn in clinopyroxene studied is the highest ever recorded in marbles in the Czech Republic, and one of the highest found in natural clinopyroxenes worldwide, with the exception of a unique Zn-deposit of Franklin, New Jersey, USA (Essene and Peacor 1987). It is close to the Zn-richest clinopyroxenes of Pb-Zn skarns of Åm¬meberg and Langban, Sweden, and the Nakatatsu mine, Japan, which contain up to ~10,000 ppm Zn, whereas the clinopyroxenes from other localities display mostly concentrations not exceeding ~1,500 ppm Zn (Huber et al. 2012, Fig. 4). The experimental study of Huber et al. (2012) has shown that an increasing petedunnite component in pyroxene shifts its stability fields to higher pressures in a similar way as the jadeite component, and there is also negative correlation between the petedunnite component in clinopyroxene and fS2/fO ratio, as well. It is assumed that the main reason for Zn entering the clinopyroxenes and the absence of spinels in the studied marbles was due to the existence of a convenient protolith showing low Al/Si and fS2/fO ratios, high Si activity in fluids, and up to granulite facies metamorphism. [ABSTRACT FROM AUTHOR]

Tourmalinites (Tu+Qtz+Ms+Chl±Grt) from the Krkonoše-Jizera Crystalline Massif form stratiform layers hosted in mica schists (Ms+Qtz+Grt+Chl±Tu±Bt). The tourmaline usually exhibits three compositional domains. The oldest Mg- rich tourmaline (Mg/(Mg+Fe) = 0.81 - 0.99) with fine-grade zoning volumetrically predominates. Mg-rich tourmaline is replaced on the rim by schorl-dravite (Mg/(Mg+Fe) = 0.51 - 0.69), and locally in muscovite rich layers is partly to fully replaced by tourmaline following trend between schorl-dravite and foitite-magnesio-foitite (Mg/(Mg+Fe) = 0.42 - 0.65). The volumetrically dominant Mg-rich tourmaline is alkali (0.59 - 0.85 apfu Na; 0.04 - 0.39 pfu xvac; 0.03 - 0.19 apfu Ca), enriched in Al (6.14 - 7.09 apfu), and calculated wO2- (0.25 - 0.87 apfu O). It typically follows trend along a join between „oxy-dravite“ and dravite. „Oxy-dravite“ (+ oxy-schorl) molecule (average 53 %) usually predominates over dravite (+schorl) molecule (average 23 %). The most prominent substitution is represented by the exchange vector Al3+O2- (Mg,Fe)2+ -1(OH)-1-1. Magnesio-foitite (+ foitite) molecule varies between 4 - 39 % (average 16 %). Positive correlation between F and Ca indicates that F entered into the tourmaline structure via fluor-uvite component (4 - 19 %; average 8 %). Mg-rich tourmaline is an early formed, premetamorphic, and genetically related to sulfide deposit formations in closely associated amphibolites. Major and trace element composition indicates its formation during interaction of Al, Mg-rich vulcanosedimentary protolith with B-rich fluids. On the contrary, both generations of later schorl-dravite are interpreted to be metamorphic. [ABSTRACT FROM AUTHOR]

Rare supergene minerals of the crandallite-group (florencite-(Ce), goayzite, crandallite), thometzekite and walpurgite were found at the material from abandoned Sn-W deposit Cínovec, the Krušné hory Mountains, northern Bohemia, Czech Republic. Crandallite-group minerals form strongly zoned orange to crystals up to 400 µm in cavities of quartz - cassiterite - wolframite gangue. Scheelite, clay minerals and mixite were observed in association. Thometzekite forms yellow or yellow green aggregates up to 2 mm on cavities of quartz gangue in association with segnitite, fluorite, opal and mixite. Thometzekite is monoclinic, space group C2/m, the unit-cell parameters refined from X-ray powder data are: a 9.141(12), b 6.361(5), c 7.646(8) Å, β 116.92(6) ° and V 396(1) ų. Walpurgite was found as groups of well-formed lath-like light yellow crystals up to 2 mm in the length in cavity of quartz gangue. It is triclinic, space group P-1, the unitcell parameters refined from X-ray powder data are: a 7.138(3), b 10.430(6), c 5.495(5) Å, α 101.51(5), β 110.97(4), Υ 88.15(4)° and V 373.9(6) ų. The quantitative chemical data for all described mineral phases are given. [ABSTRACT FROM AUTHOR]

Supergene mineral assemblages rich in Pb, As and P occur on the dumps after the historical mining of the base -metal deposit in Kvasetice (Havlíčkův Brod ore district, Bohemian-Moravian Highlands, Czech Republic). The primary hydrothermal assemblage of pyrite > sphalerite > arsenopyrite > galena >> boulangerite hosted in the quartz veins is partly different from other similar localities in this area, which belong to the typical k-pol ores with iron-rich sphalerite, pyrrhotite, pyrite, arsenopyrite and chalcopyrite. Kvasetice locality is characterized by a relatively higher stability of pyrite and sphalerite with a relatively low Fe content (< 0.12 apfu of Fe) compared to arsenopyrite and galena in supergene conditions, as well as a total deficit of Cu, Ca and partly S. In the supergene mineral association rich in Pb-P-Fe-As, two main assemblages can be distinguished. Supergene assemblage I contains common microscopic anglesite replacing galena and two sub-groups of arsenates with sulphide relics in small quartz veins: (a) in close association with the relic arsenopyrite are pharmacosiderite and hydroniumpharmacosiderite, both relatively Pb-rich (≤ 0.18 apfu of Pb), accompanied by a rare scorodite. (b) More abundant assemblage of segnitite >> beudantite > mimetite >> carminite and coronadite without a direct association with sulphides. Other phases with a non-stoichiometric Fe/As ratio (HFA) are only locally found. A sporadic greenockite is the only detected decomposition product of sphalerite. The Pb-Fe3+ sulfates (minerals of the jarosite subgroup), gypsum, and Ca-, Zn-, Sb- and Cu-supergene minerals are missing. Supergene assemblage II is mainly represented by pyromorphite (mostly with As below detection limit, but locally with ≤ 0.44 apfu), rarely by mimetite and only locally also by cerussite. They overgrow thin crusts of mainly Fe-oxyhydroxides covering the altered granite matrix or line thin druse quartz veinlets. The supergene mineral assemblages from Kvasetice differ not only from other localities in the ore district studied, but also from other localities of supergene mineralization in the Bohemian-Moravian Highlands. They are the product of weathering in the shallow supergene zone, however, they could also have been arised by subrecent weathering of materials deposited on the dumps during the 13-16th century. [ABSTRACT FROM AUTHOR]

Small Cu-Mo ore deposit near Vidly pod Pradědem (2.5 km south of Vrbno pod Pradědem, Czech Republic) is formed by ore disseminated in polyphase-metamorphosed blastomylonites of the Orlík Block nappe. A rare local oc- curence of Bi minerals whose aggregates do not exceed 600 μm, is restricted mainly to small grains (< 2 - 200 μm in size) hosted by pyrite or within boundaries between pyrite and chalcopyrite. Pilsenite is a dominating mineral phase, joséite-A, joséite-B, native Bi, tsumoite and tetradymite are less frequent. Cosalite containing ~ 4 wt. % Ag and solid solution phases lillianite - gustavite (4 to 8 wt % Ag) are frequent too. The origin of the assemblage of Bi minerals can be linked to the metamorphic processes in the wider area. In the Jeseníky Mts., the Bi minerals of the same genetic position have been described from Zlaté Hory and Zlatý Chlum near Jeseník deposits. [ABSTRACT FROM AUTHOR]

An interesting association of rare carbonate minerals was found in the dump material at the Dušní (Gesiter) vein in Jáchymov, Czech Republic. The mineral assemblage is represented by chalconatronite and abundant čejkaite. Moreover, additional mineral phase was found to be growing inside chalconatronite aggregate. It goes most probably about Na-Ca carbonate, pirsonnite or gaylussite, however, the exact identification cannot be done. Chemical composition of the studied chalconatronite was determined base on electron microprobe data. The empirical formula can be expressed as Na2.01(Cu0.98Fe0.01)Σ0.99[(PO4)0.02(AsO4)0.01(SiO4)0.01]Σ0.04(CO3)1.95 . 3H2O (mean of 4 spot analyzes; Na+Cu+Fe = 3 apfu). The refined unit-cell parameters of chalconatronite from the powder X-ray diffraction data (for the monoclinic space group P21/n) are a = 9.699(4), b = 6.098(3), c = 13.792(6) Å, β = 91.88(4)o and with V = 815.3(4) ų. [ABSTRACT FROM AUTHOR]

Porcellanite (fine-grained buchite) occurs at the contact of the dyke of Neogene basanite at Mladĕjov, Jičín District, North Bohemia. The dyke penetrated the sediments of the Březno Formation in the Jizera development of the Czech Cretaceous Basin. The protolith of the pocellanite was calcareous siltstone composed predominantly of quartz, clay minerals with dominancy of illite and carbonate (calcite represented by shells and detritus of both macro- and microfos-sils, mainly foraminifers, echinoderms and gastropods). The metamorphic assemblage corresponds to sanidinite facies and contains quartz + K-feldspar + anorthite + clinopyroxene + orthopyroxene + glass with minor pyrrhotite and accessory ilmenite, titanite and apatite. The groundmass of porcellanite is formed predominantly by quartz + K-feldspar + orthopyroxene whereas the assemblage anorthite + clinopyroxene occurs as pseudomorphs replacing calcitic shells of microfossils and calcic detritus of organic origin which shape remained frequently well-preserved despite of high-grade of pyrometamorphism. Elevated Cr in clinopyroxene gives evidence of the influence of fluids from the basanite. The presence of quartz and absence of tridymite indicates temperatures 840 - 900 °C at P <0.2 Kb. Presence of ilmenite, pyrrhotite, elemental carbon (0.05 wt. % C), and analytically determined high Fe2+/Fe3+ ratio indicate low oxygen fugacity during pyrometamorphism. [ABSTRACT FROM AUTHOR]

Three selenides were found in a sample from the small uranium deposit of Černý Důl by means of WDS. None of these selenides were found at this locality before. They are relatively rare selenides: bukovite, hakite and klockmannite which are accompanied clausthalite and tiemannite. The selenides grow together intimately and make microscopic inclusions with uraninite in calcite veins. Chemical composition of studied selenides is discussed. [ABSTRACT FROM AUTHOR]

Rare supergene Zn-Cu arsenate, zincolivenite, was found in remnants of mine dumps of the abandoned Stříbrná 2 adit at NW margin of the Krupka town, Krušné hory Mountains, northern Bohemia, Czech Republic. It forms coatings and crusts up to 1 cm² which are rarely composed by hemispherical aggregates up to 0.1 - 2 mm in size. Tiny tabular crystals (up to 8 - 10 µm) were observed at their surface. Zincolivenite is translucent, light green with bluish or yellowish tint. White hydrozincite, colourless gypsum and red brown „limonite" were found in the association. Zincolivenite is orthorhombic, space group Pnnm, the unit-cell parameters refined from X-ray powder data are: a = 8.456(2) b = 8.465(2), c = 5.986(1) Å, V = 428.9(1) Å ³. Chemical analyses yielded the average composition CaO 0.11, FeO 0.38, PbO 1.00, CuO 17.45, ZnO 36.42, Al2O3 1.42, As2O5 39.70, P2O5 0.14, SO3 0.34, H2O (3.44), total (100.10) wt. %, corresponding to the formula (Zn1.27CU0.62Al0.08Pb0.01Ca0.01)∑1.99[(AsO4)0.98(PO4)0.01(SO4)0.01]∑1.00(OH)1.09 on the basis of 1 atom in anion site. Chemical composition of the studied zincolivenite is compared to published data. The origin of zincolivenite at Krupka is interpreted as the product of weathering of primary sulfides in conditions of mine dumps deposited at the earth surface. [ABSTRACT FROM AUTHOR]

Rare supergene Cu-Zn carbonates, aurichalcite and rosasite, were found in 2007 in remnants of mine dumps of abandoned ore deposit at slope of the Sachrův hřbet hill above Horní Rokytnice (part of Rokytnice ned Jizerou), western Krkonoše Mountains, northern Bohemia, Czech Republic. Aurichalcite forms traslucent crystalline aggregates up to 1 cm in size with markedly sky-blue surface. Its elongated and thinly tabular crystals up to 1.5 mm in length are very brittle with a perfect cleavage and distinct pearly luster. They are transparent and colourless with light bluish tint. Aurichalcite is monoclinic, space group P21lm, the unit-cell parameters refined from X-ray powder data are: a = 13.812(1), b = 6.4041(8), c = 5.8060(8) Å, β = 100.71(1),° V = 461.14(9) ų. Chemical analyses yielded the average composition CaO 0.01, FeO 0.05, PbO 0.74, CuO 15.90, MnO 0.02, ZnO 51.61, Sb2O3 0.04, CO2 (14.69), SiO2 0.06, As2O5 0.06, SO3 0.11, H2O (9.02), total (92.32) wt. %, corresponding to the formula (Zn3.78Cu1.19Pb0.02)∑4.99[CO3)1.99 (SO4)0.01]∑2.00(OH)5.97 on the basis of 5 atoms in cation sites. Rosasite forms thin, irregular coatings up to 1 mm² on aurichalcite and rarely hemispherical aggregates up to 0.3 mm in size. It is translucent to opaque with indistinct greyish green colour and pearly luster. Surface of its aggregates ere ussualy smooth, its columnar crystals up to 10 µm were observed only rarely. The average results of five chemical analyses are: CaO 0.02, FeO 0.03, PbO 0.38, CuO 39.01, MnO 0.01, ZnO 22.77, CO2 (16.90), SiO2 0.06, As2O5 0.03, P2O5 0.11, SO3 0.04, H2O (6.90), total (86.26) wt. % corresponding to (Cu1.27Zn0.72)∑1.99(CO3)0.99(OH)1.99 on the basis of 2 atoms in cation sites. Chemical composition of both studied Cu-Zn carbonates is compared with published data. The succession of origin of supergene minerals inferred from the samples studied is as follows: hemimorphite → aurichalcite → rosasite. [ABSTRACT FROM AUTHOR]

Rare uranyl mineral boltwoodite, was found in the mine dump material at the abandoned uranium deposit Kladská, Slavkovský les Mountains, western Bohemia, Czech Republic. It occurs there as yellow to yellowish orange crystalline aggregates, veinlets and coatings in hydrothermally altered porphyric granite in association with uranophane. Its aggregates are usually composed from very thin acicular crystals. Well-formed boltwoodite crystals up to 2 mm in length in tiny cavities of crystalline aggregates of boltwoodite were observed only rarely. It is monoclinic, space group P21/m, the unit-cell parameters refined from X-ray powder diffraction data are: a 7.072(7), b 7.060(4), c 6.654(6) Å, ß 105.06(7)° and V 320.8(5) ų. Chemical analyses of boltwoodite correspond to the empirical formula (K0.62Pb0.04)S0.66(UO2)0.96(SiO3 OH)1.00·1.5H2O on the basis of Si = 1 apfu. The Raman spectrum of boltwoodite and its tentative interpretation are given. The origin of boltwoodite at Kladská is interpreted as product of late hydrothermal fluids which altered uraninite and granitic rocks. [ABSTRACT FROM AUTHOR]

The barite mineralization at site Hrubá skála close to Pecka village (6 km E from the town Nová Paka) was known earlier from a short discovery report. It was re-examined by geological, mineralogical, and geochemical methods. Vein mineralization is developed in a significant tectonic zone hosted by mostly coarse-grained conglomerates to sedimentary breccias of the Brusnice Member (Westphalian D to Cantabrian, Pennsylvanian) of the Kumburk Formation, which is the basal unit of the Krkonoše Piedmont Basin. Barite is present as white crystalline masses or well-developed tabular crystals up to 6 x 4 cm in size, accompanied with minor quartz. Chemically it is pure barite with Sr content less than 0.003 apfu and Ca and Fe bellow 0.001 apfu. Cell parameters are a = 8.8861(1), b = 5.4561(7), c = 7.1584(9) Å. Barite contains aqueous all-liquid (L) or rarely L+V fluid inclusions with variable liquid-vapor ratios and variable salinity (3.5 - 16.5 wt. % NaCl eq.) containing NaCl. and CaCl2. The δ34S value of barie sample is +16.9 ‰ CDT. Both fluid inclusion and sulfur isotope data are comparable to those of monomineral post-Variscan barite veins of the Bohemian Massif. Locality Hrubá skála is probably one of the best available sites to study barite mineralization in the Late Paleozoic limnic basins in the Czech Republic. [ABSTRACT FROM AUTHOR]

A hydrated uranyl copper arsenate, mineral metazeunerite, was found in the material from burned coal mine dump at the abandoned uranium and coal deposit Bečkov near Trutnov, north-eastern Bohemia, Czech Republic. Metazeunerite forms very light green irregular aggregates up to 1 mm composed by tiny (2 - 20 µm) tabular crystals in association with white anglesite aggregates and white gypsum crystals at fragments of caustic metamorphosed rocks. Metazeunerite is tetragonal, space group P4/n, the unit-cell parameters refined from X-ray powder diffraction data are: a 7.090(1), c 17.439(3) Å and V 876.6(3) ų. Chemical analyses correspond to the empirical formula (Cu0.78Al0.21K0.12 Na0.05Pb0.05Zn0.03Ca0.01)Σ1.25(UO2)2.00[(AsO4)1.42(PO4)0.34(SO4)0.18(SiO4)0.06]Σ2.00. 8H2O on the basis (As+P+S+Si) = 2 apfu. A possibility that metazeunerite formed from hot gases in conditions of burning coal mine dump is discussed in the paper. [ABSTRACT FROM AUTHOR]

Rare supergene Bi-uranyl arsenate, walpurgite, was found in material from the vein No. 18 at the abandoned adit No. 1 at the Medvĕdín uranium deposit, Krkonoše Mountains, northern Bohemia, Czech Republic. Walpurgite occurs there as bright yellow tabular crystals with characteristic greasy to vitreous lustre which form isolated aggregates up to 5 mm in size or rich crusts with area up to some cm² at fissures and cavities of quartz gangue. Eulytite, bismutite, zeunerite and unnamed (BiO)8(UO2)(PO4)3(OH).nH2O were found in the association. Walpurgite is triclinic, space group P-1, the unit-cell parameters refined from single-crystal X-ray data are: a = 7.1199(9), b = 10.389(1), c = 5.4935(8) Å, α = 101.48(1), β = 110.63(1), Υ = 88.04(1)o and V = 372.41(9) ų. The crystal structure of walpurgite has been refined to R1 = 9.79% on the basis of 1637 unique reflections [Iobs.>3σ(I)] collected on a Oxford Diffraction Gemini diffractometer with a CCD detector and MoKα radiation. Chemical analyses of walpurgite yielded the average composition CaO 0.07, ZnO 0.07, Al2O3 0.05, Bi2O3 58.26, SiO2 0.10, As2O5 10.87, P2O5 1.78, V2O5 0.14, UO3 18.23, H2Ocalc. 2.21, total 91.78 wt. % corresponding to the empirical formula (Bi4.07Ca0.02Al0.02Zn0.01)Σ4.12 (UO2)1.04O4(AsO4)1.54(PO4)0.41(SiO4)0.03(VO4)0.02]Σ2.00 . 2H2O on the basis (As+P+Si+V) = 2 apfu. [ABSTRACT FROM AUTHOR]

This paper summarizes historical knowledge of pegmatite occurrences in the vicinity of the Skalsko near Jílové u Prahy (central Bohemia, Czech Republic) and presents the results of a new field and laboratory research. The granite pegmatites near Skalsko were subject of intensive mining of feldspar for ceramic industry especially during the 19th century. The pegmatites are spatially and genetically bound to western part of Hercynian intrusion of biotitic granodiorite of the Požáry type (I - type granite), which forms a part of Central Bohemian Plutonic Complex. Pegmatites, similary as aplites and aplitic granites, usually form subhorizontal embedded bodies with zonal structure with a predominance of granitic and blocky units. A part of pegmatite veins is characterized by anomalous accumulations of molybdenite (average content of about 0.19 wt. % Mo) and thus represents a unique type of Mo ores in the Bohemian Massif, although having a limited extent. Pegmatites have relatively simple mineral composition: K-feldspar, albite, quartz, molybdenite, biotite, occasionally muscovite, apatite and rarely tourmaline. The presence of coarse- and fine-grained aggregates of molybdenite and thinly columnar aggregates of apatite is characteristic. The dominant older K-feldspar (with content up to 3.97 wt. % BaO) is intensive replaced by younger much Ba-richer (4.43 - 9.81 wt. % BaO) K-feldspar. Ba-rich K-feldspar also contains very tiny barite grains. The occurrence of abundant monazite-(Ce) and xenotime-(Y) grains (up to 100 µm in size) is characteristic for aggregates of fluorapatite (with various REE contents). The rare zonal garnet corresponds to Mn-rich almadine with higher content of spessartite component (42 - 43 mol. %) in marginal parts of its aggregates. Biotite (annite) contains higher concentration of Ba (about 0.4 wt. % BaO) and low F (about 0.5 wt. %). The flat to dome embedded pegmatite bodies are formed by predominant older granitic and younger block units, sometimes in asymmetrically repeated positions. The structure of pegmatite bodies indicates their origin in flat fissures with an extense character; sometimes with fuzzy transition between magmatic and hydrothermal stages. Older authors mostly assumed the molybdenite origin in younger hydrothermal stage (and only spatial relation of molybdenite and pegmatites); the results of this new study confirmed that molybdenite is an integral part of pegmatites. Pegmatites from the vicinity of Skalsko has some features of NYF pegmatites (low P in feldspars, elevated Y in garnet) with specified molybdenite enrichment. [ABSTRACT FROM AUTHOR]