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Zipserite is a new mineral species discovered in a sample collected from the old mine dumps of the abandoned epithermal deposit Nagybörzsöny in Hungary. Zipserite occurs as anhedral to subhedral, lath-like grains, up to 500 μm in size, in hydrothermally strongly altered rocks. It is found at a contact between bismuth and bismuthinite, also associated with rare ikunolite and joséite-A. Zipserite is silvery white with a metallic lustre. Mohs hardness is ca. 2–3 and the calculated density is 7.815 g.cm–3. In reflected light, zipserite is grey–white, with colour and reflectance essentially matching those of bismuthinite. Bireflectance is weak, internal reflections not present. Anisotropy is moderately strong, with dark blue and grey colours of anisotropy. Reflectance values for the four Commission on Ore Mineralogy wavelengths of zipserite in air [ R max, R min (%) (λ in nm)] are: 48.4, 46.4 (470); 47.8, 45.9 (546); 47.8, 45.8 (589); and 47.5, 45.6 (650). The empirical formula, based on electron-microprobe analyses, is (Bi4.74Pb0.31)Σ5.05(S3.38Se0.56Te0.02)Σ3.96, that can be simplified as Bi5(S,Se)4. The ideal end-member formula of zipserite is Bi5S4, which requires Bi 89.07 and S 10.93, total 100 wt.%. Zipserite possesses a fascinating crystal structure. The average structure is trigonal, with space group P $\bar{3}$ m , a = 4.162(1) Å, c = 16.397(1) Å, V = 245.94(4) Å3 and Z = 2. The structure is built by the alternation of a double bismuth layer Bi2 and the Bi3S4 block which is a three octahedra thick layer. Its general formula can be expressed as Bi2 + Bi3S4, which corresponds directly to the observed stacking. At 98 K, the structure can be described using the superspace formalism with an R -centred trigonal unit cell a = 4.209(2) Å, c 0 = 5.616(6) Å, a modulation vector q ≈ 4/3 c* and the superspace group R $\bar{3}$ m (00γ)00. Zipserite is not only a new mineral but also the first named member of a new sub-group of compounds within the broader family of bismuth chalcogenides, characterised by complex stacking of structural units (Bi2 layers and Bi3S4 blocks). Some of these phases are being investigated as promising thermoelectric materials and synthetic analogues of zipserite could also be inspected for similar physical properties. [ABSTRACT FROM AUTHOR]

As the calcite crystals grew, micrometer-sized terra rossaderived mineral particles likely attached to the surfaces of growing calcite crystals, creating zones in the host calcite. Keywords: Calcite; cap carbonate; clay; dolomite; hematite; goethite; illite; kaolinite; nanoparticle; nucleation; phantom crystal; phyllosilicate; Raman spectroscopy; SEM; Snowball Earth; TEM; XRD EN Calcite cap carbonate clay dolomite hematite goethite illite kaolinite nanoparticle nucleation phantom crystal phyllosilicate Raman spectroscopy SEM Snowball Earth TEM XRD 1369 1377 9 07/05/22 20220701 NES 220701 Introduction A phantom crystal is a crystal embedded in another crystal of the same mineral species with visible outlines. Phyllosilicate nucleation on calcite and dolomite nucleation on phyllosilicates, as inferred from nanoscale mineralogical associations, suggest that carbonates can also provide surfaces for the growth of phyllosilicates, and this mutual enhancement may result in the formation of large-scale clay-carbonate successions in aqueous settings. [Extracted from the article]

Tourmalinites occur in early-Paleozoic metamorphic rocks of the Gemeric Unit near Zlatá Idka village, Western Carpathians, eastern Slovakia. Tourmaline compositions, analyzed with the electron microprobe, include a wide range of tourmaline species. Tourmaline in tourmalinites from Zlatá Idka is compositionally variable, with the dominant substitution Mg-Fe2+ consistent with prevalent schorl-dravite compositions and their fluor- and oxy-dominant counterparts - fluor-schorl, fluor-dravite, oxy-schorl and oxy-dravite. Portions of tourmaline are enriched in Ca in the form of the fluor-uvite and magnesio-lucchesiite components. A subset of the compositions has Ti > 0.25 atoms per formula unit (apfu) and corresponds to the hypothetical “magnesio-dutrowite”, Mg-dominant analogue of dutrowite. In addition, some of the tourmalines are X-site vacant and classified as foitite. The crystal chemistry of tourmaline is complex and influenced by several exchange mechanisms, including Mg(Fe)-1, Al□(Mg,Fe)-1Na-1, AlO(Mg,Fe)-1(OH)-1 (Mg,Fe)CaAl-1Na-1, MgCaOAl-1□-1(OH)--1, Ti0.5O(Fe,Mg)-0.5(OH)-1 and TiMg(Al)-2 substitutions. In general, tourmalines in all samples usually have oscillatory-zoned dravitic cores and schorlitic rims (Tur I). However, in ZLT-4 and ZLT-6 samples, some crystals have secondary Mg-dominant and Ca-enriched overgrowths (Tur II), partially replacing Tur I. Tourmalinites were most likely produced by regional or contact metasomatic processes, likely due to the intrusion of the Permian Poproč granitic massif. Origin of tourmalinites likely results from the flow of late-magmatic to early post-magmatic B,F-rich fluids from the granite intrusion into adjacent metamorphic rocks. The tourmaline crystallization and its resulting chemical composition were controlled by both the metapelitic host rock and the granitic intrusion; the Mg-rich cores of the Tur I are most likely compositionally related to the metapelitic host rock, whereas later schorlitic to foititic compositions in rims suggest origin due to the intrusion-triggered fluid flow. The significant changes and oscillations of tourmaline zoning imply a dynamic, unstable fluid regime. The late Ca-rich Tur II could result from subsequent metasomatic processes associated with the alteration of host-rock minerals. [ABSTRACT FROM AUTHOR]

Up to date, 21 new minerals have been described from 14 Slovak deposits. Another 39 minerals have provided invaluable information on the scientific knowledge and diversity of individual minerals on Earth. On the territory of Slovakia, the world's most famous locality of occurrence is mainly euchroite, scainiite, hodrušite, kobellite, mrázekite, schafarzikite, vihorlatite, skinnerite, telluronevskite and brandholzite. On a European scale, examples are precious opal from Dubník, sernarmontite from Pernek and kermesite from Pezinok. While preserving the mineral heritage, it is important to preserve, in particular, the type and rare minerals, especially in large national museums and collections, and to deposit other cotype material into other (and private) collections in order to preserve them for future generations in unforeseen circumstances. [ABSTRACT FROM AUTHOR]

In this paper we describe the first occurrence of cobaltpentlandite in Slovak Republic. Cobaltpentlandite was found in borehole the R-1 in depth 677 m in Ca-Mg skarn at the Cu-Au skarn-porphyry deposit Vysoká-Zlatno. One grain of cobaltpentlandite forms euhedral crystal up to 0.014 mm in size and it is chemically homogenous. It occurs in assemblage with pyrrhotite, magnetite, monticellite, calcite, anhydrite, minerals of ellestadite and garnet group (andradite, kerimasite), anhydrite, perovskite and valleriite. Average of seven precise microprobe analyses gave empirical formula (Co5.71Fe1.77Ni1.62Cu0.01)Σ9.11S7.89. Cobaltpentladite contains up to 13.02 wt. % Fe, 12.65 wt. % Ni and 0.16 wt. % Cu. Its chemical composition is characteristic by dominantly positive correlation of Fe and Ni and by negative correlation (Fe, Ni)Co-1. Presence of opposite correlation is questionable. Origin of cobaltpentladite is related to adjacent Fe-dominant phases, pyrrhotite and magnetite, which formed in Ca-Mg skarn during younger hydrothermal sulphide stage together with galena and sphalerite. [ABSTRACT FROM AUTHOR]

Oxy-schorl (IMA 2011-011), ideally Na(Fe2+2Al)Al6Si6O18(BO3)3(OH)3O, a new mineral species of the tourmaline supergroup, is described. In Zlatá Idka, Slovak Republic (type locality), fan-shaped aggregates of greenish black acicular crystals ranging up to 2 cm in size, forming aggregates up to 3.5 cm thick were found in extensively metasomatically altered metarhyolite pyroclastics with Qtz+Ab+Ms. In Přibyslavice, Czech Republic (co-type locality), abundant brownish black subhedral, columnar crystals of oxy-schorl, up to 1 cm in size, arranged in thin layers, or irregular clusters up to 5 cm in diameter, occur in a foliated muscovite-tourmaline orthogneiss associated with Kfs+Ab+Qtz+Ms+Bt+Grt. Oxy-schorl from both localities has a Mohs hardness of 7 with no observable cleavage and parting. The measured and calculated densities are 3.17(2) and 3.208 g/cm3 (Zlatá Idka) and 3.19(1) and 3.198 g/cm3 (Přibyslavice), respectively. In plane-polarized light, oxy-schorl is pleochroic; O = green to bluish-green, E = pale yellowish to nearly colorless (Zlatá Idka) and O = dark grayish-green, E = pale brown (Přibyslavice), uniaxial negative, ω = 1.663(2), ε = 1.641(2) (Zlatá Idka) and ω = 1.662(2), ε = 1.637(2) (Přibyslavice). Oxy-schorl is trigonal, space group R3m, Z = 3, a = 15.916(3) Å, c = 7.107(1) Å, V = 1559.1(4) Å3 (Zlatá Idka) and a = 15.985(1) Å, c = 7.154(1) Å, V = 1583.1(2) Å3 (Přibyslavice). The composition (average of 5 electron microprobe analyses from Zlatá Idka and 5 from Přibyslavice) is (in wt%): SiO2 33.85 (34.57), TiO2 <0.05 (0.72), Al2O3 39.08 (33.55), Fe2O3 not determined (0.61), FeO 11.59 (13.07), MnO <0.06 (0.10), MgO 0.04 (0.74), CaO 0.30 (0.09), Na2O 1.67 (1.76), K2O <0.02 (0.03), F 0.26 (0.56), Cl 0.01 (<0.01), B2O3 (calc.) 10.39 (10.11), H2O (from the crystal-structure refinement) 2.92 (2.72), sum 99.29 (98.41) for Zlatá Idka and Přibyslavice (in parentheses). A combination of EMPA, Mössbauer spectroscopy, and crystal-structure refinement yields empirical formulas (Na0.591Ca0.103⇔0.306)Σ1.000(Al1.885Fe2+1.108Mn0.005Ti0.002)Σ3.000(Al5.428Mg0.572)Σ6.000(Si5.506Al0.494)Σ6.000O18 (BO3)3(OH)3(O0.625OH0.236F0.136Cl0.003)Σ1.000 for Zlatá Idka, and (Na0.586Ca0.017K0.006⇔0.391)Σ1.000(Fe2+1.879Mn0.015 Al1.013Ti0.093)Σ3.00(Al5.732Mg0.190Fe3+0.078)Σ6.000(Si5.944Al0.056)Σ6.000O18(BO3)3(OH)3(O0.579F0.307OH0.115)Σ1.000 for Přibyslavice. Oxy-schorl is derived from schorl end-member by the AlOFe-1(OH)-1 substitution. The studied crystals of oxy-schorl represent two distinct ordering mechanisms: disorder of R2+ and R3+ cations in octahedral sites and all O ordered in the W site (Zlatá Idka), and R2+ and R3+ cations ordered in the Y and Z sites and O disordered in the V and W sites (Přibyslavice). [ABSTRACT FROM AUTHOR]

Delafossite was found in the upper parts of the mine tailing Slovinky. Micro Raman spectroscopy, electron microprobe analysis (EMPA) and X-ray microdiffraction were used for identification of delafossite. The Raman spectrum of delafossite measured at 532 nm is characterized by two main bands at 351 cm-1 and 689 cm-1. The average empirical formula of delafossite is (n = 7): Cu1.00Fe1.01O1.99. Lattice parameters of delafossite refined by the Rietveld method were acquired by Le Bail decomposition and are following: a = 3.038(1) Å, b = 17.167(6) Å and V = 137.27(7) ų. Based on its texture, chemical composition and micro Raman data, delafossite probably comes from the primary quartz-siderite- sulphide mineralization. Delafossite occurs as compact grains or relics in goethite and malachite or in the form of botryoidal aggregates together with goethite and malachite. We suppose that delafossite has undergone an oxidation process and forms goethite and malachite in the environment of the mine tailing. From the primary minerals the most common ones are siderite, quartz, pyrite and chalcopyrite, less common ones are gypsum, muscovite, arsenopyrite and tetrahedrite. The most frequent supergene mineral is goethite, less common ones are malachite and cuprite. Covellite in the form of blue coating on chalcopyrite was observed scarce. [ABSTRACT FROM AUTHOR]

Supergene native silver and acanthite were identified at the Jasenie-Soviansko base metals deposit, Nízke Tatry Mts., Slovak Republic. Both minerals occur in cavities of quartz-sulfide vein material together with cerussite, weathered tetrahedrite, barite and quartz crystals. Native silver forms typical wire aggregates up to 2 mm which are closely associated with heavily weathered tetrahedrite. It shows increased content of S (up to 4.02 wt. %) and As (up to 1.48 wt. %) as well as small amounts of Cu (up to 0.44 wt. %), Hg (up to 0.31 wt. %), Bi (up to 0.28 wt. %) and Cd (up to 0.15 wt. %). Small, but the stable content of Cl (up to 0.24 wt. %) was also detected in native silver. Two different forms of acanthite were observed. The first form is represented by the thin black aggregates and rims of supergene acanthite on native silver and weathered tetrahedrite. For this type small contents of Sb (up to 4.62 wt. %), Cu (up to 2.30 wt. %), As (up to 1.14 wt. %), Fe (up to 0.91 wt. %) and Cl (up to 0.12 wt. %) are characteristic. The second form of acanthite is represented by groups of spear-like crystals which completely cover wires of native silver. Native silver and the first form of acanthite are products of in situ decomposition of Ag-rich tetrahedrite in the supergene zone. The second form of acanthite was formed as result of interaction of native silver and hydrosulfide in the atmospheric conditions. [ABSTRACT FROM AUTHOR]

Numerous microscopic inclusions of cassiterite, ferrotapiolite (?), „hydroxycalciomicrolite", gahnite, magnetite, fluorapatite, barite, pyrite, sphalerite, galena, muscovite, and bertrandite or phenakite occur in coarse-grained beryl, microcline, albite and quartz from the core zone of the Moravany nad Váhom, Striebornica granitic pegmatite (western Slovakia). Anhedral cassiterite inclusions reveal near end-member composition (0.2 - 0.3 wt. % Nb2O5, ≤0.06 wt. % Ta2O5). Widespread gahnite inclusions in beryl contain high iron concentrations (14 to 18 wt. % FeO, 37 to 47 mol. % of hercynite), unusual for pegmatite environment. Uranoan „hydroxycalciomicrolite" (7 - 9 wt. % UO2) forms zonal crystals in quartz-microlite veinlets in beryl. Fluorapatite inclusions locally contain thin zones enriched in strontium (~2.3 wt. % SrO), whereas barite is usually Sr-rich (~3 to 6 wt. % SrO). The mineral inclusions originated from primary magmatic crystallization (gahnite, magnetite, fluorapatite, ferrotapiolite?, possibly barite and sulphide minerals) to hydrothermal stage of the pegmatite origin (cassiterite, bertrandite or phenakite, „hydroxylcalciomicrolite", possibly barite and sulphide minerals). [ABSTRACT FROM AUTHOR]

The rare Hg-sulfosalt, marrucciite, with ideal formula Hg3Pb16Sb18S46, was found in the Gelnica ore deposit (Spišsko-Gemerské Rudohorie Mts., Slovak Republic). It occurs as acicular crystals up to 0.5 mm in length and fine-grained aggregates up to 1 mm in quartz (+siderite/dolomite) gangue in association with other sulfosalts (zinkenite, scainiite, boulangerite, chalcostibite, bournonite) and cinnabar. It is opaque, dark steel grey to greyish black, sometimes tarnished to a bronze-brown tint, has a dark grey streak with a very weak reddish tint and a metallic luster. Marrucciite is very brittle but thin acicular crystals are flexible. One good cleavage parallel to the elongation of the crystals was observed. The VHN20g microhardness is 85 (69-101) kp/mm² and corresponds to a Moh's hardness ofc. 2; the calculated density is 6.00 g.cm-3. In reflected light, marrucciite is white to greyish white with a weak yellowish tint, distinct bireflectance and white-white grey pleochroism. Under crossed polars, it has distinct anisotropy, with rotation tints in shades of grayish brown and dark brown. Dark red internal reflections were observed only rarely. Marrucciite is monoclinic, space group C2/m with a 48.12( 1 ), b 4.1083(2), c 23.990(5)/Å, β 118.76(2)°, V 4158.(3) ų. Its average composition (electron microprobe data in wt. %) is Cu 0.03, Hg 7.83, Cd 0.02, Fe 0.06, Zn 0.02, Pb 43.13, Sn 0.03, Sb 29.15, Bi 0.12, S 19.71, CI 0.05, total 100.15. The empirical formula on the basis 83 of apfu is Hg2.93(Pb15.63Fe0.08Cu0.04Cd0.02Zn0.02Sn0.02)∑15.81 (Sb17.97Bio0.04)∑18.01(S46.14Cl0.11)∑46.25. The crystal structure of marrucciite from Gelnica contains two Hg positions (6 atoms), 7 Pb positions (28 atoms), 8 Sb positions (32 atoms), two mixed Pb-Sb positions (refined as Pb0.39Sb0.61 and Pb0.61Sb0.39) and 23 S positions (46 atoms). [ABSTRACT FROM AUTHOR]

Brandholzite, a hydrated hydroxide of Mg2+ and Sb5+, was found at the Krížnica deposit near Pernek (Malé Karpaty Mountains, Slovak Republic); it is the third occurrence of this mineral phase worldwide. Crystals and crusts of brand-holzite occur as surface coatings on altered shales mineralized with stibnite and pyrite. Associated minerals include roméite-like phases, sulphur, aragonite, gypsum, sénarmontite and Sb-rich Fe-hydroxides. Brandholzite forms euhedral tabular crystals of hexagonal habit, typically 0.5 to 0.8 mm across, exceptionally up to 2 mm long. The crystals occur as isolated, or randomly grouped individuals, creating inconspicuous crusts up to several cm2. Brandholzite crystals are colourless, transparent or showing white clouding. No fluorescence was observed under either short- or long-wave UV radiation. The average electron microprobe analysis gave 6.11 MgO, 0.52 CaO, 0.16 FeO, 55.89 Sb2O5 and (37.32) H2O if recast to 100 wt. %. The calculated formula is (Mg0.88Ca0.05Fe0.01)Σ0.94(H2O)6.00[Sb(OH)6]2.00. The XRD pattern was indexed in a trigonal setting (space group P3), with refined unit-cell parameters a = 16.1076(9), c = 9.8628(9) A and V= 2216.1(2) Å. The thermogravimetric curve shows total weight loss of 34.6 wt. % (over the interval of 20-800 °C), caused by H2O release. The initial rapid weight decrease (20-140 °C) was followed by a minor continuous weight loss up to 800 °C. Brandholzite from Pernek and its mineral association were probably formed by sub-recent weathering processes in an abandoned mines environment. [ABSTRACT FROM AUTHOR]

Rare supergene antimony sulphate klebelsbergite was found in the abandoned mine adit at 1st vein system of the Kremnica epithermal Au-Ag deposit, Slovak Republic. It forms yellow or white radial and spherical aggregates up to 3 mm, which are consisted of tabular and acicular crystals. Aggregates of klebelsbergite form crusts on the weathered stibnite. The unit-cell parameters of klebelsbergite are a = 5.7596 (6), b = 11.2678 (11), c = 14.8576 (9) Šand V = 964.24 (12) ų. Klebersbergite consists of major elements Sb, S and O exclusively as shown by qualitative chemical analysis. Klebelsbergite is a product of (sub)recent weathering of stibnite in acid environment of the mine adit. [ABSTRACT FROM AUTHOR]

The first occurrence of Ag-Pb-Sb sulphosalts was described from Sb mineralization in Tatric Unit in the Western Carpathians. Rare microscopic grains of andorites up to 0.05 mm were identified in antimony deposit Dúbrava (Nízke Tatry Mts., Central Slovakia). Andorites forms inclusions in stibnite. According to microprobe analyses andorite IV and andorite VI were distinguished. Crystallochemical formulas of andorites are following: andorite IV: (Ag13.40Cu2.89)Σ16.29 (Pb15.69Cd0.42Fe0.08Zn0.05Hg0.02)Σ16.26(Sb45.92Bi0.09)Σ46.01 (S97.31CI0.12)Σ97.43 (And95.88) and andorite VI: (Ag0.76CU0.24)Σ1.00 (Pb0.99 Cd0.02)Σ1.01(Sb3.03Bi0.01)Σ3.04(S5.94Cl0.01) Σ5.95(And100.17)- Cu content in andorite VI (1.73wt. %, 0.24 apfu) isthe highest content measured value this element in andorites up to now. Andorite substitution And96.50 is yet highest relevant amount of substitution in andorite IV. Ag-Pb-Sb sulphosalts represented Sb-rich members of lillianite hometypic series (4L) crystallized in final stage after precipitation of stibnite. No further minerals were identified in this mineral assemblage. For andorite IV it is the first occurrence of this mineral in the Slovak Republic. [ABSTRACT FROM AUTHOR]

Minerals of tourmaline group in veins are described from several occurrences (Predsvätodušna, Svätodušná, and Podlipa) in the area of the L'ubietová Cu-deposit. They have hydrothermal or hydrothermal-metamorphic origin and take a part in alpine paragenesis in association with quartz, albite, muscovite, chamosite, pyrite, rutile and other accessories. The chemical composition and fluid inclusions on tourmalines were examined. Tourmalines from L'ubietová are chemically homogeneous, and they belong to the alkali group with schorl to schorl/dravite composition. The FeMg-1 a Na(MgFe)↔-1Al-1 (foitite) substitutions have the strongest influence on the occupancy of the tourmaline structural sites X and Y. Fluid inclusions in schorl from the Podlipa deposit are formed by the aqueous solution and vapour phase. The homogenization temperatures of fluid inclusions range from 122.3 °C to 226.9 °C (183.6 °C in average). The average ice-melting temperature was -6.6 °C, and the average salinity of fluid inclusions was 10.2 hm. % NaCl eq. (calculated from the ice-melting temperature). Chemical composition of tourmaline and results of fluid inclusion study indicate metamorphic origin of fluids and intermediate temperature of the tourmaline crystallization. Very high amount of inclusions and defects, weak zoning, dull colour and the cataclastic destruction of crystals disable any gemologic application of tourmalines from the L'ubietová deposit. [ABSTRACT FROM AUTHOR]

Mineralization, involving vanadian-chromian silicates, has been studied in Lower Paleozoic, carbon-rich amphibole schists with pyrite and pyrrhotite near Pezinok, southwest Slovakia. A detailed electron microprobe study has revealed the presence of V,Cr-rich garnet, clinozoisite, and muscovite, associated with amphiboles (magnesiohornblende, tremolite, actinolite, and edenite), diopside, and albite. The garnet contains 5-19 wt% V2O3, 5-11 wt% Cr2O3, and 2-13 wt% Al2O3 (16-64 mol% goldmanite, 19-36 mol% uvarovite, and 9-59 mol% grossular end-members). The garnet is unzoned or shows V-rich cores and Al-rich rims, or irregular coarse oscillatory zoning with V, Cr, and Al, locally involving Ca and Mn as well. The V,Cr-rich clinozoisite to mukhinite and "chromian clinozoisite" contains 2-9.5 wt% V2O3 and 1.5-11 wt% Cr2O3; the muscovite contains 2.5-8 wt% V2O3 and 0-7 wt% Cr2O3. The mineralization originated from primarily V-, Cr-, and C-rich mafic pyroclastic rocks, affected by volcano-exhalative processes. These rocks were weakly metamorphosed during early Hercynian regional metamorphism (M1), followed by late-Hercynian contact metamorphism (M2) with crystallization of V,Cr-rich silicates, diopside, amphiboles, phlogopite, titanite, albite, quartz, carbonate, pyrite, and pyrrhotite. The youngest Alpine(?) retrograde metamorphic event (M3) is connected with production of V,Cr-poor muscovite, clinochlore, clinozoisite, pumpellyite-(Mg), prehnite, quartz, and carbonates, under prehnite-pumpellite facies conditions. [ABSTRACT FROM AUTHOR]

The article presents new knowledge on a study of silica rock (limnosilicite) with electron microscopy on the locality Banské in the Slanské vrchy Mts., Eastern Slovakia. We studied five colour varieties of silicites- black, light brown, dark brown, gray and white color, and the cause of these colour variations. Chemical composition of black, grey and white silicite is characterized by high dominance of Si, only black one contains 0.07 wt.% Fe2O3. Brown varieties contain up to 2.68 wt.% Fe2O3. White and grey colour of limnosilicite is the same original colour in which quartz and chalcedony crystallize. Black colour of limnosilicite is probably caused by submicroscopic carbonized organic rests. Brown colour is caused by the presence of iron hydrooxides, which have been formed by the decomposition of pyrite. Pyrite occurs mainly in the form of framboids that are the product of sulphur bacteria activity. [ABSTRACT FROM AUTHOR]

Granitic pegmatite vein (ca. 15 cm thick) containing Be-minerals occurs in granite from the Sitina tunnel in Bratislava, SW Slovakia. Dark grey quartz, white to dark grey microcline, milky-white albite (partially variety cleavelandite) and muscovite are main minerals of the pegmatite. Accessory minerals include garnet (almandine), chlorite and mica (biotite) and Be-bearing minerals: beryl and phenakite. Beryl shows increased concentrations of Mg (up to 0.35 apfu), Fe (up to 0.14 apfu) and Na (up to 0.48 apfu). Average crystallochemical formula of beryl is following (n=12): Na0.46Be3.00 Al1.52Mg0.32Fe0.12Si6.04O18. The Fe,Mg-rich composition and high c/a lattice ratio (0.9916) indicate a presence of octa-hedral beryl type. Phenakite is a part of younger generation of quartz crossing the beryl crystal. [ABSTRACT FROM AUTHOR]

We describe hydrothermal base metal mineralization, which has not yet been particularly investigated in previous works. Small mine dump occurs in quartz-biotite paragneissis near Valaská Belá in the Strážovské vrchy Mts., the western part of Slovak Republic. Primary filling of the hydrothermal vein is formed by quartz, carbonates, galena, sphalerite, chalcopyrite, pyrite, tetrahedrite and bournonite. Our research was oriented on the interesting supergene zone. Cerussite as well as pyromorphite is the most abudant secondary mineral. Transparent cerussite crystals are up to 3 mm in size. The unit-cell parameters of cerussite are a = 5.175 (2), b = 8.486 (2), c = 6.136 (2) Å and V = 269.5 (1) ų. Yellow to yellow-green pyromorphite occurs in three morphological forms -- fine-like, globular and chaotically grown crystals on matrix. The pyromorphite unit-cell parameters a = 9.986 (2), c = 7.353 (2) Å and V = 635.1 (3) ų suggest low substitution P→As. Chemically clear hemimorphite forming tabular crystals grouping to radial aggregates up to 2 mm in size has unit-cell parameters a = 8.352 (3), b = 10.697 (4), c = 5.107 (3) Å and V = 456.3 (3) ų. X-ray pattern and unit-cell parameters of orange wulfenite (a = 5.432 (1), c = 12.110 (3) Å and V = 357.4 (2) ų) forming dipyramidal crystals up to 2 mm in size are the first analytical data after a 80 years from Slovak Republic. Hemimorphite crystalized single in cavities and fissures and succesion other secondary minerals is as follows: cerussite → pyromorphite → wulfenite. [ABSTRACT FROM AUTHOR]

Rare Cu-Bi sulphosalt, hodrušite, occurs in the Rozália vein (levels X-XIV of the Rozália mine, Hodruša-Hámre ore deposit near Banská Štiavnica, central Slovakia) in two unusual morphological forms. The first type are brownish bronze thin acicular striated crystals, up to 3 mm long, in drusy cavities of quartz-hematite gangue, which are usually grouped into chaotic or irregular aggregates. The second hodrušite type comprises flattened columnar aggregates, up to 1.5 cm in length, overgrown by hematite in quartz gangue. These aggregates are distinctly striated with brownish bronze colour and metallic lustre. Abundant W- and Al-rich hematite, chalcopyrite, kaolinite/dickite, siderite, baryte, rare bismuthinite and kupčíkite were found in the association. The earliest columnar aggregates of hodrušite are locally substantially replaced by bismuthinite; these hodrušite-bismuthinite aggregates are further intensively pushed back by hematite displaying W- and Al-rich zones. Acicular crystals of hodrušite in gangue cavities were later than bismuthinite and hematite and their formation was related to remobilisation of Cu and Bi from earlier altered gangue. Powder X-ray diffraction data and chemical composition of both hodrušite types are similar; their unit-cell parameters were refined (monoclinic space group C2/m) as: a 17.552(5), b 3.905(1), c 27.167(9) Å, β 92.44(3)o, V 1860.5(9) ų (acicular crystals) and a 17.567(2), b 3.9151(7), c 27.155(5) Å, β 92.43(1)o, V 1865.9(4) ų (columnar aggregates). Cu-for-Bi substitution is characteristic of both hodrušite types; it influences calculated Nchem values (0.98-1.33) to the point that it is impossible to distinguish hodrušite (ideal 1.5) from kupčíkite (ideal 1.0). The problem is resolved by Fe and Ag contents: kupčíkite has more than 2 at. % Fe, cuprobismutite contains more than 2 at. % of Ag; hodrušite usually has Ag and Fe contents below 2 at. %. Hematite is remarkable for its high WO3 content reaching 4.96 wt. % (0.04 apfu), extremely unusual of a hematite from hydrothermal vein mineralization. Tungsten probably enters the hematite structure via the 2Fe3+?W6++ n substitution. [ABSTRACT FROM AUTHOR]

The Pb-Zn mineralization occurence at the Marianka village (SW Slovakia) is hosted by Paleozoic metapelitic rocks of the Tatric Unit. The mineralization occurs in quartz-carbonate-sulphidic lenses. Sphalerite and galena are the most abundant ore minerals, accompanied by bournonite, boulangerite, meneghinite, pyrite, chalcopyrite, tetrahedrite, marcasite and pyrrhotite. Quartz is the main gangue mineral. The other non-sulphidic minerals are calcite, ankerite, siderite and dolomite. Microthermometric measurements of fluid inclusions in quartz suggest that Pb-Zn mineralization was deposited probably from the low to middle salinity fluids of two generations (ø 5.1 and 18.8 wt.% NaCl eq.) at minimum temperature range of 100 - 150°C. The mineralization have 2 stages: 1. Carbonate-quartz and 2. Sulphidic, represented by older paragenese (pyrite-chalcopyrite-sphalerite) and younger sulphosalts-galena mineral assemblage (with boulangerite, bournonite and meneghinite). [ABSTRACT FROM AUTHOR]

Native bismuth forms rare aggregates (up to 1 mm across) in quartz core of the beryl-type granitic pegmatite from Bratislava, Švábsky Hill (Malé Karpaty Mts., Slovakia). The pegmatite dike (<1 m thickness) cuts parental Hercynian S-type granites of the Bratislava massif. The bismuth shows homogeneous, nearly end-member composition (only 0.2 wt.% Sb). It is partly replaced by bismite and bismutite along the rims. Native bismuth precipitated during inal hydrothermal stage of the pegmatite crystallization at temperature 250 - 260 °C, whereas supergene bismite and bismutite are products of late oxidation and weathering processes, or low-temperature alteration of the bismuth. [ABSTRACT FROM AUTHOR]

Kerimasite Ca3Zr2(Fe3+ 2Si)O12, a rare member of garnet supergroup, was identified by EMPA in Ca-Mg skarn on the contact between Miocene granodiorite porphyry intrusion and Middle Triassic dolomites in a borehole from the Cu-Au skarn-porphyry deposit Vysoká-Zlatno near Banská Štiavnica (Štiavnické Vrchy Mts., Central Slovakia). Kerimasite forms isolated irregularly shaped grains (60 - 100 µm across) in association with andradite, monticellite, clintonite, magnetite, perovskite and brucite. Kerimasite originated during prograde metamorphic conditions of high-temperature contact thermal metamorphism related to emplacement of the granodiorite porphyry into dolomites. [ABSTRACT FROM AUTHOR]

Epidote was found in Permian rift-related metabasalts in two localities near Lošonec and Sološnica, Malé Karpaty Mountains, SW Slovakia. It occurs in association with calcite, albite, clinochlore and titanite and forms fillings of veins and also smaller scattered veinlets cutting basalts. Epidote is chemically and structurally similar on both localities. It has a relatively weak chemical zoning with Al-enriched core and Fe3+-rich rim of crystals. It is slightly enriched in Sr which contains up to 2.15 wt.%, 0.100 apfu. This enrichment in Sr is likely the result of geochemical properties of host rock, which locally contains up to 1000 ppm Sr. Lattice parameters of epidote from Lošonec (a = 8.9067(8) Å, b = 5.6382(6) Å, c = 10.1724(9) Å, β = 115.33(1)°, V = 461.72(4) ų) and Sološnica (a = 8.9075(8) Å, b = 5.6404(5) Å, c = 10.1742(8) Å, β = 115.39(1)°, V = 461.78(7) ų) also reflect the substitution of Sr for Ca. Mineral assemblage with epidote and associated minerals is likely a product of Alpine hydrothermal processes as a part of Alpine-type paragenesis. [ABSTRACT FROM AUTHOR]

Fine-crystalline to massive datolite has been identified as nodule and fracture fillings in Permian rift-related metaba-salts near Lošonec village, Malé Karpaty Mountains, SW Slovakia. The electron-microprobe and X-ray diffraction data [a = 4.8365(2) Å, b = 7.6120(5) Å, c = 9.6353(5) Å, β = 90.128(6)°] indicate a nearly pure datolite end-member. Datolite associates with quartz, calcite, talc/stevensite and hematite (goethite?). It precipitated probably from post-magmatic (hydrothermal) boron-rich fluids of volcanic origin. [ABSTRACT FROM AUTHOR]

Schröckingerite was found in the abandoned 5. kvìěten adit of the Vrchoslav hydrothermal fluorite deposit, the Krušné hory Mountains, northern Bohemia, Czech Republic. It forms green-yellow globular to irregular crystalline aggregates with pearly luster up to 3 mm in diameter on the fragments of rocks and walls of adit. Schröckingerite aggregates are formed by small thin tabular crystals up to 0.07 mm with obviously parallel orientation. Rarely in association with schröckingerite there also were bright orange powdery aggregates of natrozippeite observed. The unit-cell parameters of schröckingerite refined from powder X-ray data are: a = 9.6279(9) Å, b = 9.6303(9) Å, c = 14.3868(11) Å, α = 91.360(9)°, β = 92.292(10)°, γ = 120.191(6)° and V= 1150.59(6) ų. In the infrared spectrum of schröckingerite, the bands of (CO3)2-, (SO4)2- and (UO2)2+ groups as well as molecular H2O were identified. The bond-lengths with values of 1.762 Å, 1.778 Å and 1.769 Å depending on the empirical formula used were calculated from the wavenumber of uranyl bands. Schröckingerite was formed as a sub-recent supergene phase in relatively dry environment from the solutions produced by weathering of the primary U phases (uraninite) associated probably with Nb-Ta minerals in granite and rare pyrite and their interaction with calcite and wall rocks. [ABSTRACT FROM AUTHOR]

Pseudomalachite was found at mine dumps of the occurrence Breziny, about 200 m northern from the Henclová village, the Slovenské Rudohorie Mountains, Slovak Republic. It forms hemispherical aggregates and crusts (up to 3 x 3 cm in size) in the cavities of quartz gangue in association with malachite, goethite and rare relics of primary chalcopyrite. Surface of its spherical aggregates is formed by tiny (up to 80 µm) tabular crystals. Pseudomalachite aggregates are dark green, non-diaphanous and they have a shimmer to vitreous luster. Pseudomalachite is monoclinic, space group P21/c, the unit-cell parameters refined from X-ray powder data are: a = 4.4799(5), b = 5.7485(7), c = 17,061(2) Å, β = 91.13° (1), V = 439.27(6) ų. The ED analysis at electron microprobe confirmed results of X-ray diffraction study; Cu, P and O were found as main constituents. [ABSTRACT FROM AUTHOR]

Pilsenite, ideally Bi4Te3 was found in the body of hydrothermal metasomatites, which is located near Poruba pod Vihoraltom, Vihoralt Mts., Slovak Republic. It forms lead-grey, subhedral grains up to 7 mm in size with typical perfect cleavage. Pilsenite grains are often grouped into the aggregates and clusters up to 3 x 2 cm, which are embedded in brownish metasomatite. Its refined unit-cell parameters from the powder X-ray diffraction data (for the trigonal space group R-3m) are a = 4.430(4), c = 41.834(3) Å with V = 710.971(1) ų. The chemical composition of pilsenite is close to the end member and apart from Bi and Te only minor contents of Pb (up to 0.06 apfu), Se (up to 0.03 apfu) and S (up to 0.03 apfu) were detected. Its average empirical formula is (Bi3.95Pb0.05)Σ4.00(Te2.96Se0.02S0.02)Σ3.00 on the basis of 7 apfu. [ABSTRACT FROM AUTHOR]

The abandoned deposit Dobšiná in eastern Slovakia used to be exploited for Ni-Fe-Co sulfarsenides in siderite-ankerite hydrothermal veins. These veins are locally accompanied by alteration zones of fuchsite-quartz-carbonate rocks. The Ni-Fe-Co sulfarsenides are postdated by chalcopyrite and tetrahedrite. This work aims to determine the age of these mineralizations utilizing U/Pb, Re/Os, and K/Ar dating of selected minerals. U/Pb dating of hydrothermal siderite and ankerite gave ages from 145 ± 5 Ma to 114 ± 24 Ma. They broadly coincide with the metamorphic peak in the Gemeric Unit and the formation of the Gemeric cleavage fan (CGF) during partial exhumation of this unit. Hydrothermal gersdorffite was dated (Re/Os) to 93.6 ± 0.9 Ma, the time of exhumation of the Gemeric unit. No data were extracted for the younger Cu sulfides. By correlation with other units in the Western Carpathians, they could be assigned Late Cretaceous age, corresponding to welding of the Gemeric and Veporic units and the formation of the Trans-Gemeric shear zone. The fuchsite rocks were dated (K/Ar) to 110 Ma, but this datum conflicts with textural evidence, which shows that these rocks are older than the hydrothermal carbonates. The age of 110 Ma is therefore considered to be cooling age after the reset of the geochronometer by the Alpine metamorphism, in agreement with earlier data. The geochronological results are supported by structural measurements and field observations. The main mineralized zone, investigated in one of the accessible adits, conforms with the Variscan - ?Alpine metamorphic foliation. There are also younger, less significant structures whose relevance to the ore mineralization is not yet clear. [ABSTRACT FROM AUTHOR]

The quartz veins with primary fluorapatite, xenotime-(Y), monazite-(Ce) to monazite-(Nd), uraninite, and secondary florencite-(Ce) and goyazite occur in Lower Devonian metavolcano-sedimentary sequence of the Gelnica Group, Gemeric Superunit, the Central Western Carpathians (eastern Slovakia). They represent an example of hydrothermal REE-U mineralization. Fluorapatite forms parallel bands of columnar crystals (≤ 3 cm) in massive quartz. Monazite- (Ce) to (Nd) shows a near end-member composition with very small amounts of cheralite and huttonite components. Widespread xenotime-(Y) forms colloform aggregates or irregular aggregates in association with fluorapatite and monazite. Uraninite electron-microprobe U-Pb dating gave the average age o f207 ± 2 Ma (n = 16, 2σ), which is consistent with formation of the U mineralization in the Gemeric Superunit (e.g., Kuriskova uranium deposit) during early Alpine hydrothermal activity. [ABSTRACT FROM AUTHOR]