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This paper describes a newly discovered Bi-Cu±Au mineralization co-occurring with Pb-Zn-Ag hydrothermal mineralization within the Kizhnica-Hajvalia-Badovc ore field, central Kosovo, Vardar Zone. The mineralogy of two styles of Bi-Cu±Au mineralization was described using EPMA in combination with reflected and transmitted light microscopy. Hydrothermal Cu-Bi veinlets in the Kizhnica andesite quarry consist of Bi sulfosalts (bismuthinite, cosalite, aikinite, and krupkaite), pyrite, hematite, chalcopyrite, galena, sphalerite, and tetrahedrite group minerals. Disseminated Bi-Au-Cu-Te mineralization from the contact type of mineralization (hornfels) consists of Bi sulfosalts (cannizzarite, bismuthinite, galenobismutite, cosalite), associated with sulfarsenides (arsenopyrite, gersdorffite, and cobaltite), base metal sulfides (chalcopyrite, pyrite, sphalerite, pyrrhotite, and galena), native gold, native bismuth, and tetradymite. LA-ICP-MS analyses of sphalerite, chalcopyrite, and tetrahedrite indicate increased content of In and Sn in the Kizhnica Bi-Cu-Au mineralizing system, while LA-ICP-MS analyses in pyrites show the presence of many elements, e.g., Au, As, Co, Sb, Tl, Hg, Pb, Bi related to the structure of pyrite or controlled by nano-inclusions. The results suggest a connection between Bi-Cu±Au mineralization and the proximity to intrusive rocks, which may be helpful for Au exploration in Kosovo.

Primary ore mineralization in the abandoned Boguszów baryte-polymetallic deposit, located in the Intra-Sudetic Depression, was studied by reflected light microscopy and electron microprobe. Ore minerals, occurring as veinlets, irregular aggregates and lenses in baryte veins are hosted by the Upper Carboniferous Chełmiec rhyodacite laccolith. They are dominated by galena, sphalerite (with Cd up to 0.04 apfu) and tetrahedrite group minerals (TGM). Four generations of the TGM were distinguished according to textural features and Ag content: (1) low-Ag tetrahedrite-(Zn) (Ag: 0.22–0.6 apfu), (2) Ag-enriched tetrahedrite-(Zn) and Ag-enriched tetrahedrite-(Fe) (Ag: 0.71–1.45 apfu), (3) members of the freibergite series: “freibergite-(Fe)” and “freibergite-(Zn)” (Ag: 3.21–3.48 apfu; Hg: up to 0.75 apfu), (4) member of the “freibergite-(Fe)” series (Ag: 5.32–5.78 apfu). Several elongated inclusions of Ag-bearing sulphosalts within galena crystals were observed (members of the series “freibergite-(Fe)” and “freibergite-(Zn)”, pyrargyrite and polybasite). These polymetallic silver-bearing ores were mined in Boguszów from the 15th to the 19th century. Additionally, small grains of cobalt-enriched löllingite and gersdorffite were observed, which were formed from fluids sourced from the ultramafic basement. The textural characteristics of the ore, the mineral paragenesis and the chemical composition of individual ore minerals indicate low-temperature crystallization conditions.

Unique association of sulphosalts was discovered at the Kl’ačianka occurrence, Nízke Tatry Mts., Slovak Republic. It is bound to thin hydrothermal veins with Sb mineralization hosted by the Variscan muscovite-biotite granodiorite and granite of Prašivá type. Ore mineralogy and crystal chemistry of ore minerals are studied here by ore microscopy, X-ray powder diffraction, electron microprobe analyses, and Raman spectroscopy. The early ore mineralization composed of pyrite and arsenopyrite is hosted in quartz gangue and is followed by abundant association of sulfos-alts. Stibnite, zinkenite, robinsonite (including Cu-bearing variety), jamesonite, scainiite, dadsonite, disulfodadsonite, rouxelite, chovanite, semseyite, boulangerite, geocronite, tintinaite (with low Bi contents), tetrahedrite-(Fe), tetrahedrite-(Zn), bournonite, chalcostibite, bismuthinite, and gladite in association with sphalerite and rare galena and gold are identified here. The chlorine-rich character of the described sulphosalt association is its characteristic phenomenon. It is represented not only by the occurrence of Cl-sulphosalt and dadsonite, but increased Cl contents were detected in boulan-gerite, chovanite, disulfodadsonite, robinsonite, rouxelite, scainiite, or tintinaite. The presence of oxygen-containing sulphosalts, such as rouxelite, scainiite and chovanite, is also interesting. The crys-tallization of these rare chloro-, oxy-and oxy-chloro-sulphosalts at the Kl’ačianka occurrence required very specific conditions (elevated O2 /S2 fugacity) and high chlorine activity in ore-forming fluids.

Agate samples collected from the vicinity of Asni and Agouim (Western Atlas, Morocco) were investigated using microscopic observations supported by Raman micro-spectroscopy. The agates are marked by the presence of various microtextures typical of epithermal vein deposits, including jigsaw-puzzle, feathery, and lattice-bladed. The first two indicate that the formation of agates was likely marked by recrystallization of metastable silica phases (i.e., opaline silica or massive chalcedony). The presence of lattice-bladed (after barite and calcite) quartz may be, in turn, ascribed to the boiling-related conditions that could have triggered the formation of abundant copper and iron sulfides found within silica matrix. Additionally, the local occurrence of growth lines (so-called Bambauer quartz) and intergrowth of length-slow and length-fast chalcedony are linked to the variations of physico-chemical conditions during rock formation (alkaline-acidic). According to Raman spectroscopy, silica matrix of the agates is made of &alpha, quartz with a local admixture of moganite (from 0.0 up to 78 wt.%), but also contains numerous solid inclusions of hematite, celadonite, as well as poorly-organized carbonaceous material and rutile. These phases were likely emplaced during low-temperature hydrothermal activity of SiO2-bearing fluids that originated from post-magmatic hydrothermal activity developed within host rocks and/or meteoric waters.

Stannite group minerals (ferrokësterite and stannite) occur in small amounts in association with sulfides in hydrothermal Pb-Zn deposits in Kosovo. The chemical composition of sphalerite co-existing with Sn-bearing minerals has been investigated using laser ablation inductively-coupled plasma mass spectrometry (LA-ICP-MS). Flat Sn-spectra suggest that Sn is bound in the sphalerite lattice or as nanoincluions. Sphalerite from Stan Terg, overgrown by ferrokësterite, contains the lowest Sn content (few ppm) and have been precipitated before Sn-enrichment in the fluids. The highest value of Sn (520 ppm) of Stan Terg sphalerite was obtained directly close to the ferrokësterite rim, and indicates a rapid increase of Sn in the hydrothermal fluids. Significantly higher values of Sn in sphalerite were obtained from other deposits: 1600 ppm (Artana), up to 663 ppm (Kizhnica), up to 2800 ppm (Drazhnje). Stannite-sphalerite geothermometry revealed the following ore-forming temperatures for the Kosovo mineralization: 240–390 °C for Stan Terg, 240–370 °C for Artana, >340 °C for Kizhnica, and 245–295 °C for Drazhnje. Sphalerite and stannite group minerals precipitated simultaneously during cooling from reduced hydrothermal fluids and under low-sulfidation fluid states. Fluctuations in physico-chemical fluid conditions are evidenced by the presence of stannite group minerals along growth zones in sphalerite and may be related to short interval of magmatic pulses during ore deposition.

An interesting association of the Bi sulfosalts was identified in the Rozalia mine, Hodrusa–Hamre, Slovakia. Sulfosalts of the cuprobismutite series are the most common, and occur in paragenesis with other Bi sulfosalts, chalcopyrite and hematite. Members of the pavonite homologous series are associated with bismuthinite derivatives and quartz of the amethyst variety. Three members of the cuprobismutite homologous series and four members of the pavonite homologous series have been found in a hydrothermal base-metal mineralization in the Rozalia mine. Kupcikite has the structural formula (Cu 6.73 Fe 1.10 ) ∑7.83 (Bi 9.49 As 0.36 Ag 0.24 ) ∑10.09 (S 18.89 Se 0.13 ) ∑19.02 ; that of hodrusite is (Cu 7.69 Fe 0.38 ) ∑8.07 (Bi 11.22 As 0.34 Ag 0.53 ) ∑12.09 (S 21.99 Se 0.17 ) ∑22.16 , and that of cuprobismutite is (Cu 7.47 Fe 0.14 ) ∑7.61 (Bi 12.81 As 0.69 Ag 1.38 ) ∑14.88 (S 23.85 Se 0.22 ) ∑24.07 . Makovickyite has the structural formula Cu 1.14 Ag 0,99 Pb 0.13 Bi 5.07 S 8.94 Se 0.06 ; that of pavonite is Cu 0.43 Ag 0.82 Fe 0.03 Pb 0.19 Bi 2.84 S 4.96 Se 0.04 , that of dantopaite is Cu 2.29 Ag 3.68 Fe 0.12 Pb 1.32 Bi 12.02 S 21.85 Se 0.15 , that of benjaminite is Cu 1.13 Ag 2.26 Fe 0.16 Pb 0.76 Bi 6.51 S 11.91 Se 0.09, and that of mummeite is Cu 1.44 Ag 2.61 Fe 0.41 Pb 0.95 Bi 6.70 S 12.93 Se 0.07 . The associated sulfosalts are paděraite, berryite and members of the bismuthinite–aikinite series (bismuthinite, gladite, krupkaite, lindstromite, friedrichite and aikinite).

A complex assemblage of Nb-Ta-(Sn) oxide minerals occur in a relatively narrow (~1−2 m thick) extensively albitized, Hercynian granitic pegmatite dike intruding biotite granodiorites near Bratislava, SW Slovakia. The dike shows enrichment in beryl (locally Cs-rich) but absence of Li- and B-rich phases. Compositions and textural relationships indicate complex evolutions of Nb-Ta oxide phases with several generations presenting distinct textural and compositional features. The first generation of the Nb-Ta minerals from the quartz-microcline-muscovite zone show Ta,Fe-rich compositions with Ta# [Ta/(Ta + Nb)] = 0.52−0.70 (Ct I columbite-tantalite), 0.88−0.90 (Tap I ferrotapiolite) and 0.73−0.86 (Fw I ferrowodginite); Mn# [Mn/(Mn + Fe)] = 0.32−0.49 (Ct I), 0.06−0.10 (Tap I) and 0.33−0.41 (Fw I). The 2nd generation is represented by ferrocolumbite to ferrotantalite (Ct II) in saccharoidal albite zone, replacement zones of Ct II in Ct I, and irregular overgrowths of ferrotapiolite (Tap II) and ferrowodginite (Fw II) on Tap I grains. The minerals of the 2nd generation show decreasing of Ta# in comparison to the 1st group: 0.10−0.60 (Ct II), 0.85−0.87 (Tap II) and 0.73−0.77 (Fw II); Mn# attains 0.30−0.45 (Ct II), 0.06−0.09 (Tap II) and 0.26−0.37 (Fw II). The 3rd generation includes fissure fillings, overgrowths and replacement zones of manganocolumbite and manganotantalite (Ct III), ferrotapiolite (Tap III) and ferrowodginite (Fw III) on the older Nb-Ta phases (Ct I, Tap I, Fw I, Fw II), in the coarse-grained unit. The 3rd population displays distinct Mn# increasing (Ct III: 0.51−0.69, Tap III: 0.11−0.24, Fw III: 0.40−0.41), Ta# values reach 0.16−0.79 (Ct III), 0.88−0.92 (Tap III) and 0.80−0.81 (Fw III). The latest, 4th generation of the Nb-Ta phases represents irregular veinlets and patches of fluorcalciomicrolite, replacing Ct I, Tap I, Fw I, Ct II and Tap III. Decrease of Ta/(Ta + Nb) values in Ct II from the saccharoidal albite unit can be explained by crystallization from the albite-rich melt, which was significantly impoverished in Ta with respect to Nb, after crystallization of Ta-rich phases from the 1st generation (ferrotapiolite I, ferrowodginite I).

The first documented occurrence of Nb-Ta mineralization in a granitic pegmatite from the Svalbard Archipelago, Arctic Caledonides and the relationships between primary and secondary Nb,Ta-bearing phases are discussed. The Skoddefjellet NYF pegmatite located in southwest Spitsbergen (Wedel Jarlsberg Land) is characterized by enrichment in Nb, U, Zr, Y, REE and Pb, low Zr/Hf (∼8-10), and (∼8-12) Nb/Ta ratios. Columbite-(Fe) and columbite-(Mn) (locally enriched in Ti, Y, Sc and Ca) and Nb,Ta, Y-bearing titanite (≤3.8 wt. % Nb2O5, ≤1.9 wt. % Ta2O5, ≤2.9 wt. % Y2O3) represent the primary magmatic Nb-Ta minerals. The secondary assemblage comprises Nb,Ta-bearing rutile (≤23 wt. % Nb2O5, ≤1.7 wt. % Ta2O5), ilmenite, fersmite and pyrochlore group minerals: including yttropyrochlore-(Y), plumbopyrochlore, yttrobetafite-(Y) and plumbobetafite. Internal zoning of columbite group minerals is expressed by distinct rimward increase of the Mn/(Mn+Fe) ratio (0.07 to 0.83) and low Ta/(Ta+Nb) ratio (0.03 to 0.10), suggesting alkaline environment and increasing fluorine activity during the pegmatite evolution. The formation of secondary phases is related to the hydrothermal stage of the pegmatite. Notably, the formation of Nb,Ta-bearing rutile and ilmenite seems to be a product of Nb,Ta-bearing titanite alteration.

Accessory REE minerals occur in a small metamorphic magnetite ore deposit at Bacuch, Veporic Superunit, central Slovakia. We distinguish two populations of monazite. Monazite I forms subhedral to euhedral crystals associated with magnetite. It contains ≤12 wt.% ThO2, ≤2.7% UO2, ≤0.85% SO3, with low Ca and Sr contents. Compared to the common monazite-(Ce) I, monazite-(Nd) I (≤26.1% Nd2O3) occasionally occurs with an atomic ratio Nd:Ce up to 1.17. Monazite II is present as irregular aggregates with hingganite in younger hydrothermal quartz – albite – chlorite veinlets, or as rim zones on monazite I. Monazite II is depleted in Th and U and has an unusually high content of S (≤11.3% SO3, 0.31 apfu S) and Sr (≤8.7% SrO, 0.18 apfu Sr). This composition indicates a (Ca,Sr)S(REE,Y)−1P−1 substitution as a dominant mechanism of Sr and S entry into the monazite structure. Some monazite II crystals display an elevated Eu content (≤1.2% Eu2O3). Xenotime-(Y) forms subhedral crystals, in association with monazite-(Ce) I, magnetite, pyrite transformed to goethite (?) and quartz. Gadolinite-group minerals at Bacuch are represented by hingganite with an atomic value of X □/ X (□ + Fe) in the range 0.51–0.72. Neodymium is locally the most abundant REE (17.8–18.7% Nd, ~0.56 apfu ), and an Nd-dominant member of the gadolinite group was identified. The composition of hingganite-(Y) was also determined. The principal mechanism of substitution in hingganite is Fe2+O2□−1(OH)−2. Primary monazite I and xenotime are most likely products of regional metamorphism, together with magnetite mineralization. On the contrary, Sr- and S-rich monazite II and hingganite originated during a younger (Alpine) metamorphic-hydrothermal overprint in a fluid-rich regime.

Bi-Se-Te mineralization from Úhorná (Spišsko Gemerské Rudohorie Mts., Słovakia): A preliminary reportAn unusual association of Se minerals was studied. Se enters into the structures of sulphosalts - into bournonite, jamesonite and tintinaite at concentrations up to 0.10, 0.38 and 1.11 apfu, respectively. However, Se and Te, together with Bi, also form discrete minerals such as tetradymite, laitakarite, ikunolite and hedleyite. Members of the laitakarite-ikunolite solid solution display a wide range of anion substitution from the nearly Se-free (0.10 apfu) end member to the S-poor (0.42 apfu) end member. Their contents of Te are low. Accompanying tetrahedrite does not contain Se or Te.

Mineralogy and Geochemistry of the Nižná Boca Sb-Au Hydrothermal Ore Deposit (Western Carpathians, Slovakia)Samples from hydrothermal Sb-Au mineralization in the area SE of Nižná Boca village in the N&iAzke Tatry Mountains were investigated using a variety of geochemical and mineralogical methods. Ore minerals typically occur in N-S striking quartz-carbonate veins hosted by an I-type biotite granodiorite to tonalite of Variscan Age (the Ďumbier Type). Paragenetic associations in the deposit are comparable to other mineralizations of the same type in the Ďumbierske Nízke Tatry Mountains. A quartz-arsenopyrite, pyrite stage of mineralization is the oldest with a calculated temperature of formation of about 445°C. It is followed by a quartz-carbonate-stibnite, zinkenite stage and, in turn, a quartz-carbonate-sphalerite-galena, boulangerite-gold stage. The gold typically contains between 9-18 wt.% Ag regardless of mineral association. No evidence for further generations of gold was found although it is possible that some gold was remobilized from the structure of the auriferous arsenopyrite. The Au and Ag content of the bulk ore ranges from 0.53 g.t-1to 20.2 g.t-1and from 0.9 g.t-1to 31.2 g.t-1, respectively. A tetrahedrite-chalcopyrite stage is followed by a barite-hematite stage - the youngest assemblage in the deposit. Fluid inclusions from the first mineralization stage are usually less than 3 μm in size and contain less than 3.6 wt.% CO2; salinity, density and homogenization temperature range from 2.7-16.3 wt.% NaCl(eq), 0.85-1.03 g.cm-1and 128-280°C, respectively.

A Note on the Chemical Composition of Nuffieldite Solid-Solution From Sulphide Mineralizations in the Western Carpathians, SlovakiaThe chemistry of the rare sulphosalt nuffieldite from three localities in Slovakia is examined. Nuffieldite is a part of a complex association of Bi sulphosalts accompanying tetrahedrite mineralization in some sulphide deposits in the Western Carpathians. Cu + Pb = (Bi, Sb) + vac. substitution in nuffieldite and the general formula Cu1+xPb2Bi2(PbxSbyBi1-x-y)S7where 0 < x < 0.34; and 0.32 < y < 0.45 are confirmed. Decreasing Sb content with increasing copper content indicates a predominant substitution of Bi by Sb in nuffieldite.

Three sulphosalts from the cuprobismutite homologous series have been found in a hydrothermal Ni-Bi-As mineralization at Cierna Lehota (Slovakia). Kupcikite (second world occurrence) has a significant content of Pb (2.73 wt.%) and Fe (0.85 wt.%), with the structural formula (Cu 3.92 Fe 0.24 ) Σ4.16 (Bi 4.60 Pb 0.19 Ag 0.04 Sb 0.01 ) Σ4.84 S 9.58 . Hodrushite has a higher content of Ag (mean 1.27 wt.%), but less Fe (0.59 wt.%) and Pb (0.23 wt.%), with structural formula (Cu 7.79 Fe 0.38 ) Σ8.17 (Bi 11.34 Ag 0.43 Pb 0.04 Sb 0.02 ) Σ11.83 S 22.13 . Two varieties of cuprobismutite have the highest Ag content (3.8 and 2.3 wt.%), with Fe 0.6 and 0.2 wt.%, and Pb 0.1 and 6.7 wt.%, giving two formulas (Cu 7.42 Fe 0.47 ) Σ7.87 (Bi 12.56 Ag 1.55 Pb 0.02 ) Σ14.13 S 24.68 and (Cu 7.67 Fe 0.14 ) Σ7.81 (Bi 11.95 Pb 1.37 Ag 0.85 Sb 0.02 ) Σ14.19 S 24.13 . Chemical variations between these sulphosalts are compared with published data, that emphasizes the role of minor cations. Associated sulphosalts are described: aikinite, and Bi-rich tennantite (Bi up to 9.7 wt.%).

This study reports silver mineral association found recently in the Stan Terg lead and zinc mine, located in the Vardar Zone (in the northern Kosovo). The described mineralization comprises pyrargyrite, freieslebenite, high-Ag bearing tetrahedrite, freibergite and native compounds (electrum, native silver, native antimony). Ag-minerals occur in vuggs and cracks in massive galena ore, and have signs of the latest precipitated minerals in the deposit. The chemical composition of those minerals was confirmed by the electron microprobe. Freibergite from the Stan Terg deposit reveals zonality and contains between 13.91-20.28 at. % of Ag. High Ag solutions are indicated also by relatively high silver content in electrum, which is between 47.02 and 73.19 at. % of Ag. The Ag association is supposed to be an epithermal equivalent of precious metal mineralization which could be located in the external part of the Stan Terg hydrothermal system. This association occurs in low temperatures, below 200˚C. The Ag-minerals can be part of epithermal veins from the external part of the Stan Terg hydrothermal system. Similarly to the other know Pb-Zn-Ag hydrothermal system, silver association is related to formation of the rhodochrosite banded ore and Ag-Au-Sb±Hg dominated mineralization.