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CuPbSbS3 (bournonite) has emerged as a promising light-absorbing material for thin-film solar cells due to its attractive photophysical properties. The crystallinity of CuPbSbS3 films is a main challenge of achieving high power conversion efficiency. Herein, we perform a series of optimization strategies to enhance the crystallinity of CuPbSbS3 films, including adjusting the annealing temperature and reducing the carbon residue. The optimized CuPbSbS3 film acquires an enhanced crystallinity, and an optimal solar cell device based on it achieves a power conversion efficiency of 2.65% with good stability. This efficiency is the highest value for CuPbSbS3 solar cells up to now.

Here we present a method for in situ determination of stable antimony (Sb) isotope compositions by ultraviolet (UV)-femtosecond-laser-ablation-multi-collector-ICP-MS (fs-LA-MC-ICP-MS). Metallic antimony and a number of Sb minerals (stibnite, senarmontite, chalcostibite, tetrahedrite, boulangerite, bournonite, zinkenite, pyrargyrite and dyscrasite) have been investigated. In order to verify the results of the in situ method, LA-MC-ICP-MS measurements were compared with solution MC-ICP-MS analyses on two chemically homogeneous stibnite samples and Sb metal. The internal precision of in situ measurements was better than 0.045‰. The long-term reproducibility for these three materials was better than 0.1‰. These results imply that any of these three materials may be used as an in situ Sb isotope standard. All δ123Sb values were determined by applying a standard-sample bracketing protocol and mass bias correction using Sn (NIST SRM 3161a standard solution) isotope ratios. Since no certified Sb isotope standard is currently available, in situ isotope analyses were performed in bracketing to a stibnite in-house standard and subsequently recalculated relative to NIST SRM 3102a. Matrix effects from Cu, Pb, Ag, Fe and Zn on the natural mineral Sb isotope ratios were insignificant. The mass interference of 123Te on 123Sb can only precisely be corrected for materials with Te/Sb ≤ 0.2. The LA and solution analyses of δ123Sb homogeneous zinkenite, dyscrasite and pyrargyrite agree excellently with each other. Senarmontite shows more variable δ123Sb at small scales, determined with LA-MC-ICP-MS, but homogeneous δ123Sb determined by solution analyses with a small offset between solution and LA analyses. Other minerals, like boulangerite, show heterogeneous δ123Sb (≈0.5‰) for both solution and LA analyses. Overall, these results demonstrate that fs-LA-MC-ICP-MS is suitable to measure Sb isotopic ratios in Sb-rich sulfides, sulfosalts and oxides (excluding Sb tellurides) with a precision better than 0.1‰ and a spatial resolution of ≈30 μm. Thus, it may be used as a tool to analyse spatially resolved Sb isotope composition at the mineral or even sub-mineral scale, e.g. to address the processes of ore formation or Sb redistribution in near-surface environments.

There is considerable interest in the exploration of new solar absorbers that are environmentally stable, absorb through the visible, and possess a polar crystal structure. Bournonite CuPbSbS3 is a naturally occurring sulfosalt mineral that crystallizes in the noncentrosymmetric Pmn21 space group and possesses an optimal band gap for single junction solar cells; however, the synthetic literature on this quaternary semiconductor is sparse and it has yet to be deposited and studied as a thin film. Here we describe the ability of a binary thiol-amine solvent mixture to dissolve the bulk bournonite mineral as well as inexpensive bulk CuO, PbO, and Sb2S3 precursors at room temperature and ambient pressure to generate an ink. The synthetic compound ink derived from the dissolution of the bulk binary precursors in the right stoichiometric ratios yields phase-pure thin films of CuPbSbS3 upon solution deposition and annealing. The resulting semiconductor thin films possess a direct optical band gap of 1.24 eV, an absorption coefficient ∼105 cm-1 through the visible, mobilities of 0.01-2.4 cm2 (V·s)-1, and carrier concentrations of 1018 - 1020 cm-3. These favorable optoelectronic properties suggest CuPbSbS3 thin films are excellent candidates for solar absorbers.

The Valunistoe Au–Ag deposit is the third largest among epithermal deposits in Chukotka after the Kupol and Dvoinoe. It is located at the western closing of the East Chukotka flank zone of the Okhotsk-Chukotka volcanic belt. Volcanic domes (Pravogornenskaya, Zhil’ninskaya, Shakhskaya, Valunistaya, Shalaya, and Oranzhevaya, each is 3–6 km in diameter) have the main ore-controlling significance in the area; they form a chain elongated to the northeast, along the Kanchalan fault zone. Near the deposit, Upper Cretaceous volcanics are widespread: ignimbrites, lavas and tuffs ranging from rhyolite to basaltic composition, and lenses and interbeds of sedimentary rocks, subvolcanic bodies and dikes of andesites, basalts, and dacites. The structure of the deposit is caused by its localization within the limits of the eponymous (Valunistaya) volcanic dome. Twelve ore-bearing vein zones with thicknesses ranging from several to several tens of meters have been revealed at the deposit. The Glavnaya (Main) and Novaya (New) vein zones have been studied in detail; they are traced along their strikes to a distance of more than 1500 m and consist of en echelon veins 1.0 m thick on average, with lengths varying from 100 to 400 m. Based on the sampling data, Au and Ag contents in ores are 0–474.3 and 0–3794.23 g/t, respectively. Colloform-banded structures are frequently encountered, often combined with breccia structures. The main vein minerals are quartz and adularia; calcite, chlorite, fluorite, sericite, pyrophyllite, kaolinite, montmorillonite, gypsum, and epidote are less frequent. The main ore minerals are pyrite, acanthite, chalcopyrite, galena, sphalerite; secondary ore minerals are native Au and Ag and polybasite; rare ore minerals are pearceite, magnetite, hematite, marcasite, freibergite, tetrahedrite, bournonite, hessite, matildite, and others. Ores are characterized by an Au/Ag ratio from 1 : 5 to 1 : 10 and sulfidity (0.5–5%). Ores are enriched in many elements (Au, Ag, Sb, Cd, Pb, Cu, Zn, As, Se, Mo, Te, and Cr), with enrichment factors ranging from several times (Se, Mo, Te, and Cr), to tenfold (Cd, Pb, Cu, and Zn) and hundredfold (Sb) levels, reaching an excess of tens and hundreds thousand times for Au and Ag (Fig. 7). Ores are characterized by a low total REE and demonstrate positive Eu anomalies. Geochemical features are consistent with the mineral composition of ores. Full homogenization of fluid inclusions in quartz occurs at temperatures of 203–284°C and 174–237°C in calcite, while the salt concentration in both cases is from 0.2 to 0.7 wt % NaCl equiv. Fluid density changes from 0.87 to 0.56 g/cm3. The results give grounds to attribute the Valunistoe deposit to the low-sulfidized epithermal class. The data provided in the article are of practical value for regional forecast–metallogenic maps and can be used in searching for and appraising epithermal Au–Ag deposits.

We characterize the mineralogy and geochemistry of Fe, Zn, Pb, Sb, As, Hg, Ag sulfide assemblages from mud masses currently extruded by the onshore South Sakhalin and Pugachev mud volcanoes (Sakhalin Island, Russia). Abundant Tl-rich pyrite in sulfide concentrate samples from the mud volcanoes coexists with common Hg- and Ge-rich sphalerite, as well as with sporadic boulangerite, robinsonite, bournonite, galena, realgar, metacinnabar, cinnabar, acanthite, and chalcopyrite. Sphalerites are remarkably enriched in Hg (locally reaching 27 wt%) and coupled zwith permanent abnormal enrichment in Ge (3008-3408 ppm). According to single-crystal XRD analyses and Raman spectroscopy, both Hg-poor and Hg-rich sphalerites are single-phase (Zn,Hg)S-cub compounds. Pyrite is of diagenetic origin, judging by its trace-element chemistry, particular morphology, and heavy S isotope composition. Another assemblage, composed of Pb-Sb-(Hg) sulfide minerals and lesser As, Cu, Ag, and Bi compounds, results from hydrothermal alteration and is genetically related to Neogene volcano-sedimentary rocks found among the ejecta of the mud volcanoes. The composition of impurities in sphalerite from mud masses indicates crystallization at temperatures lower than ~100 & DEG;C, under the leaching effect of mud volcano waters.

Heterogeneous rhythmic–zonal aggregates of tennantite-IV partly or completely replacing early homogeneous Zn-tetrahedrite-I grains and euhedral (Fe–Zn)-tennantite-I crystal were found in ores of the Darasun gold deposit. The different stages of fahlore replacement were observed. This initiates at grain boundaries and is terminated by a complete transformation into pseudomorphic, newly formed (Zn–Fe)-tennantite-IV aggregates surrounded by Zn-tetrahedrite-IV. These aggregates closely associate with bournonite and galena, and their precipitation initiated the formation of pseudomorphs. As is evident from the results of EMPA, (Fe–Zn)-tetrahedrite enriched in As in relation to Zn-tetrahedrite-I was precipitated at the initial stage. Tennantite with wide variations in the Sb/(Sb + As) and Fe/(Fe + Zn) ratios predominates in zonal heterogenous aggregates. There is a negative correlation between Sb/(Sb + As) and Fe/(Fe + Zn) ratios in (Fe–Zn)-tetrahedrite–tennantite-IV. In all sites, there is a miscibility gap between As and Sb and a sharp decrease in Sb/(Sb + As) ratio and increase in Fe/(Fe + Zn) ratio at the contact between Zn-tetrahedrite-I and newly formed (Fe–Zn)-tetrahedrite–tennantite-IV. The sharp zigzag boundaries between Zn-tetrahedrite-I and tennantite-IV and pores in newly formed aggregates provide evidence for coupled dissolution–precipitation reactions. The dissolution was initiated by disequilibrium between Zn-tetrahedrite-I and undersaturated fluid due to the precipitation of galena and bournonite. The precipitation of tetrahedrite–tennantite-IV occurred under the conditions of oscillation in Sb/(Sb + As) and Fe/(Fe + Zn) ratios due to the gradient of concentrations in the fluid. The temperature of crystallization of zonal heterogenous tennantite-IV aggregates ((134–161) ± 20°С) was calculated by the sphalerite–fahlore geothermometer. Instability of early Zn-tetrahedrite-I results from hydrothermal fluid cooling, decrease in fluid salinity, and change in the tetrahedrite and tennantite solubility due to the evolution of the conditions of semimetal migration.

Mineral assemblages, the peculiarities of intergrowths, chemical composition, and Sb and As distribution in coexisting fahlore and bournonite-seligmannite solid solutions of the Darasun gold deposit are studied. The almost complete solid solution between bournonite and seligmannite with continuous Sb–As isomorphism for Sb/(Sb + As) ratios from 0.21 to 1.00 is identified for the first time for the Darasun deposit using a microprobe. The composition of fahlore coexisting with bournonite widely varies: Sb/(Sb + As) ratio 0.03–0.96 and Fe/(Fe + Zn) ratio 0.36–0.87. The mutual compositional evolution from early Sb to late As coexisting solid solutions is identified. Based on the Sb and As distribution between coexisting fahlore and bournonite-seligmannite, the temperatures of their joint crystallization are estimated, as well as those of the productive stage, where they are associated with native gold and tellurides (90–335°C).

The Shurab Sb-polymetallic mineralization is a subvolcanic rock-hosted epithermal deposit and located in north Lut Block, eastern Iran. It is one of the most important deposits of the Iranian East Magmatic Assemblage (IEMA) in which numerous Middle-Cenozoic precious and base metals deposits occur. The main lithological units in the area are Paleogene subvolcanic intrusions and minor Jurassic sedimentary rocks. Mineralization occurs as veins in a series of NW-SE and E-W trending faults and fractures in the Eocene-Oligocene dacite and andesite subvolcanic rocks. Mineralization at the Shurab deposit can be subdivided into four stages: pre-ore stage, Cu-Zn-Pb ore stage, Sb-Ag ± As ore stage and post-ore stage. The total sulfide content of the veins in the area is variable, ranging from 1 to 50%, and is dominated by stibnite, chalcopyrite, galena, Fe-poor sphalerite and pyrite with minor chalcostibite, Ag-tetrahedrite and bournonite; gangue minerals are mainly quartz and calcite. Silicic, argillic, propylitic, and sericitic, are the most obvious wall rock alterations. Microthermometric measurements of primary liquid-rich fluid inclusions in quartz and sphalerite indicate that the veins were formed at temperatures between 115 and 290 °C from fluids with salinities between 0.7 and 16.2 wt% NaCl eq., suggesting an epithermal origin. The δ34S values of pyrite, chalcopyrite and galena vary between -2.5 and 0.8‰, and δ18O values of quartz range between 12.5 and 14.8‰. It is inferred that the Shurab mineralization is of epithermal origin, related to an Eocene-Oligocene magmatic geothermal system involving fluids of magmatic and meteoric origin.

The rhythmically banded aggregates of Fe–tennantite with oscillatory zoning resulting from simultaneous variations in the concentrations of Sb and As and Zn and Fe were registered in the Darasun gold deposit (Eastern Transbaikalia). These aggregates were formed upon pseudomorphic replacement of early Zn–tetrahedrite. This process was initiated by the dissolution of Zn–tetrahedrite with the formation of an aggregate of galena, bournonite, and late tetrahedrite–tennantite. It is shown that rhythmically banded aggregates with an oscillatory zoning were formed as a result of coupled dissolution–reprecipitation reactions under the conditions that are far from the mineral–fluid chemical equilibrium and variations in the fluid composition controlled by kinetic factors.

Quaternary metal chalcogenides have attracted attention as candidates for absorber materials for inexpensive and sustainable solar energy generation. One of these materials, bournonite (orthorhombic CuPbSbS3), has attracted much interest of late for its properties commensurate with photovoltaic energy conversion. This paper outlines the synthesis of bournonite for the first time by a discrete molecular precursor strategy. The metal dithiocarbamate complexes bis(diethyldithiocarbamato)copper (II) (Cu(S2CNEt2)2, (1)), bis(diethyldithiocarbamato)lead (II) (Pb(S2CNEt2)2, (2)), and bis(diethyldithiocarbamato)antimony (III) (Sb(S2CNEt2)3, (3)) were prepared, characterized, and employed as molecular precursors for the synthesis of bournonite powders and the thin film by solvent-less pyrolysis and spray-coat-pyrolysis techniques, respectively. The polycrystalline powders and thin films were characterized by powder X-ray diffraction (p-XRD), which could be indexed to orthorhombic CuPbSbS3. The morphology of the powder at the microscale was studied using scanning electron microscopy (SEM). Energy-dispersive X-ray spectroscopy (EDX) was used to elucidate an approximately 1:1:1:3 Cu/Pb/Sb/S elemental ratio. An optical band gap energy of 1.55 eV was estimated from a Tauc plot, which is close to the theoretical value of 1.41 eV., Alharbi et al. showcase an inorganic molecular precursor approach to bournonite (copper lead antimony sulfide), which has attracted attention recently as a solar absorber material for energy generation via the photovoltaic effect.

A combination of textural observations from 38 Permian Sb-Pb-Ag±Au-bearing quartz veins in the Schwarzwald (SW Germany) with isotopic, fluid inclusion, and geochemical data allows to refine genetic models for this common type of mineralization, to understand the origin of mineralogical diversity and the correlation with large scale tectonic events. Textures record four main mineralization stages: (I) Fe-As(-Sb±Au), (II) Pb-Zn-Cu, (III) Pb-Sb, and (IV) Ag-Sb. Stage I sulfides, dominated by pyrite and arsenopyrite, formed due to cooling of low-salinity metamorphic fluids during the Permian with maximum homogenization temperatures of 400 °C. Invisible gold in arsenopyrite, pyrite, marcasite, and stibnite was remobilized and locally precipitated as electrum at the end of stage I. Minerals of stages II and III comprise a rich diversity of Sb-bearing sulfosalts including, e.g., bournonite, zinkenite, and jamesonite. This assemblage formed during Jurassic times due to mixing of high-salinity, mid- and upper-crustal fluids (up to 27 wt% NaCl+CaCl2) with homogenization temperatures between 50 and 250 °C. Stage III is marked by a rich variety of Pb-Sb sulfosalts. Its local abundance is directly related to the presence of stage I mineralization and its extent of remobilization during a significant influx of Pb in the Jurassic-Cretaceous. The formation of the Upper Rhine Graben during the Tertiary reactivated especially NE-SW-oriented veins. Percolating Ag-rich fluids reacted with earlier stage III Pb-Sb sulfosalts forming Ag-rich minerals (stage IV) such as miargyrite, pyrargyrite, and stephanite. The transition from metamorphic fluids to basinal, saline (e.g., Pb-bearing) brines over hundreds of millions of years as is shown in this study and present in other Variscan occurrences indicates a possibly typical poly-stage characteristic of Sb deposits worldwide, which has, however, not been investigated in detail so far.

Natural samples containing tetrahedrite–tennantite, bournonite–seligmannite and geocronite–jordanite from the Coranda-Hondol ore deposit, Romania, were investigated by Raman spectroscopy to determine its capability to provide estimates of solid solutions in three common and widespread sulfosalt mineral series. Raman measurements were performed on extended solid solution series (Td1 to Td97, Bnn25 to Bnn93 and Gcn24 to Gcn67, apfu). The tetrahedrite–tennantite and bournonite–seligmannite solid solution series show strong correlations between spectroscopic parameters ( position, relative intensity and shape of the Raman bands) and the Sb/(Sb+As) content ratio, while Raman spectra of geocronite–jordanite shows no evolution of Raman bands. In order to simplify the method used to estimate the Sb/(Sb+As) content ratio in tetrahedrite–tennantite and bournonite–seligmannite series, several linear equations of the first-order polynomial fit were obtained. The results are in good agreement with electron microprobe data. Moreover, a computer program was developed as an analytical tool for a fast and accurate determination of Sb/(Sb+As) content ratio by at least one spectroscopic parameter. These results indicate that Raman spectroscopy can provide direct information on the composition and structure of the tetrahedrite–tennantite and bournonite– seligmannite series.

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.

The Milin Kamak gold-silver deposit is located in Western Srednogorie zone, 50 km west of Sofia, Bulgaria. This zone belongs to the Late Cretaceous Apuseni-Banat-Timok-Srednogorie magmatic and metallogenic belt. The deposit is hosted by altered trachybasalt to andesitic trachybasalt volcanic and volcanoclastic rocks with Upper Cretaceous age, which are considered to be products of the Breznik paleovolcano. Milin Kamak is the first gold-silver intermediate sulfidation type epithermal deposit recognized in Srednogorie zone in Bulgaria. It consists of eight ore zones with lengths ranging from 400 to 1000 m, widths from several cm to 3–4 m, rarely to 10–15 m, an average of 80–90 m depth (a maximum of 200 m) and dip steeply to the south. The average content of gold is 5.04 g/t and silver – 13.01 g/t. The styles of alteration are propylitic, sericite, argillic, and advanced argillic. Ore mineralization consists of three stages. Quartz-pyrite stage I is dominated by quartz, euhedral to subhedral pyrite, trace pyrrhotite and hematite in the upper levels of the deposit. Quartz-polymetallic stage II is represented by major anhedral pyrite, galena, Fe-poor sphalerite; minor chalcopyrite, tennantite, bournonite, tellurides and electrum; and trace pyrrhotite, arsenopyrite, marcasite. Gangue minerals are quartz and carbonates. The carbonate-gold stage III is defined by deposition of carbonate minerals and barite with native gold and stibnite. Fluid inclusions in quartz are liquid H 2 O-rich with homogenization temperature (T h ) ranging from 238 to 345 °C as the majority of the measurements are in the range 238–273 °C. Ice-melting temperatures (T m ) range from −2.2 to −4.1 °C, salinity – from 3.7 to 6.6 wt.% NaCl equiv. These measurements imply an epithermal environment and low- to moderate salinity of the ore-forming fluids. δ 34 S values of pyrite range from −0.49 to +2.44‰. The average calculated δ 34 S values are 1.35‰. The total range of δ 34 S values for pyrite are close to zero suggesting a magmatic source for the sulfur.

The sulfosalt minerals are of great importance for a better understanding of ore forming conditions and mineralization distribution, especially in the case of hydrothermal deposits. So far, few Raman studies were conducted on this type of minerals. In the present work, were studied several samples from Baia Sprie ore deposit, Romania—a worldwide classic example for hydrothermal mineralizations. Bismuthinite, lillianite-gustavite, heyrovskyite, cosalite, tetrahedrite-tennantite, bournonite and semseyite have been analyzed using electron microprobe and Raman spectrometry. The Raman spectra of bismuth sulfosalts, Ag-rich tetrahedrite and semseyite are discussed for the first time. The Bi sulfosalts show typical ν 1 symmetric stretching modes of the MS 6 octahedra at 286–279 cm −1 , ν 2 stretching at 216–207 cm −1 and ν 5 bending modes at 140–112 cm −1 . The transition from tetrahedrite to tennantite is very clearly observed in the Raman spectra. Several changes are marked through the solid solution, as the Sb—As isomorphic substitution takes place. Therefore, as the composition changes from As-member (tennantite) to the Sb-member (tetrahedrite), a shifting trend is observed in the Raman spectra, especially for the fundamental modes. The spectra of bournonite are dominated by two very strong lines at 325 and 296 cm −1 . The Raman band at 331 cm −1 in semseyite is assigned to ν 1 symmetric stretching modes of the octahedra. The ν 2 stretching is observed at 212 cm −1 , while the bending mode ν 5 appears at 148–143 cm −1 .

The Montevecchio-Ingurtosu district (SW Sardinia) was among the largest historical Pb-Zn producers of Italy, with significant Ag output, and yields of metallic byproducts such as Cd, Co, Cu, Bi, Sb, Ge, In, and Ga. Despite this importance, detailed descriptions of orebodies and mineral assemblages are surprisingly scarce and old. Here we summarize all previously available information and contribute new textural, microchemical, fluid inclusion, and C-O isotopic data deriving from a recent sampling of currently exposed orebodies. Mineralization occurs as steeply dipping veins extending for almost 20 km at the northern and western flanks of the Variscan Arbus pluton; veins are hosted in phyllites of the Arburese Unit close to the thermometamorphic aureole. Ore enrichments range from massive to coarsely nodular, stockwork and brecciated. Vein filling consists of siderite (locally Zn-rich), quartz, sphalerite, galena (remarkably rich in micro-inclusions), with accessory chalcopyrite, fahlore, bournonite, barite, and Ni-Co sulfarsenides. Vein assemblages may vary, even within a single vein, from sphalerite- to galena-dominated. Cu-rich assemblages (fahlore+chalcopyrite) were locally observed. Wallrock is affected by silicification, sericitization and pyrite dissemination. Sphalerite shows a complex mineral chemistry, with marked variations in Fe (0.08 to 8.9 mol% FeS) and in Cd contents (from 1 wt%). Trace element analyses (LA-ICP-MS) document the presence of measurable amounts of Ga, Ge, In, Ag, Ni, Co, Tl and Mo. Fahlore varies from the Sb (tetrahedrite) and the As (tennantite) endmembers, with Ag-rich compositions corresponding to Sb endmembers. The occurrence of Cd-rich tetrahedrite (up to 14.5 wt%) is remarkable. Fluid inclusion studies on sphalerite and quartz are in agreement with previous literature data, and indicate comparatively low (in the range 90°-130°C) homogenization temperatures (Th) and high salinities (14 to 25 equiv. mass % NaCl); both microthermometric data and SEM/EDS analyses of decrepitated inclusions indicate the presence of Ca and K beside Na. Pressure correction to Th is presumably low (in the order of 10°C), considering a hydrostatic pressure regime. Application of the sphalerite-based GGIMFiS thermometer provided temperatures in excellent agreement with fluid inclusion data for the Montevecchio mineralization. Isotopic data on Montevecchio carbonates define mildy negative delta 13CPDB values (between -1 and -5 per mil), and a larger spread of delta 18OSMOW values, between +14 and +20 per mil. Other isotopic data from literature include a limited set of delta 34S values for galena, sphalerite and pyrite, and a fairly large body of Pb isotopic data on galena. Comparatively narrow ranges for sulfur isotope signatures suggest a homogeneous, possibly igneous, sulfur source, whereas the large spread in Pb isotope signatures reflects the large-scale character of the hydrothermal process and indicates that the Arbus pluton may have been just one of the sources of ore lead. The Montevecchio vein system shows affinities with other late to post Variscan European deposits. The nature of the mineralizing fluids at Montevecchio is analogous to low temperature, basinal brines, and typical of several regional-scale, late to post-Variscan hydrothermal events across Europe. Mineralization at Montevecchio obviously postdates the emplacement of the Arbus plutonic complex, but its exact age remains unknown.

Lanping basin is a large Pb-Zn-Cu-Ag polymetallic mineral province in SW China, with major deposit types including vein-type Cu deposits, basinal brine-related Pb-Zn deposits (e.g., Liziping, Fulongchang) and minor quartz-vein-type Pb-Zn deposits (e.g., Shangnuluo, Baiji). In this study, we have conducted EPMA and LA-ICP-MS sphalerite trace element analyses, together with gangue carbonate C-O stable isotope analysis and molybdenite Re-Os dating. Using these data, we discuss the mineral assemblage, sphalerite minor/trace element composition, ore-fluid source, and mineralization age of these two types of Pb-Zn deposits. Except sphalerite and galena, major ore minerals from Liziping and Fulongchang are As-rich (e.g., gratonite, jordanite, bournonite, As-rich pyrite), whereas those from Shangnuluo and Baiji are Sb-rich (e.g., boulangerite, jamesonite, stibnite, zinkenite). The trace element compositional characteristics in sphalerite of these deposits (low Mn, Fe, Co, In and Sn, and high Cd) mimic those of medium-low-temperature hydrothermal deposits (MVT and Jinding deposits). For the Liziping zoned sphalerite, the dark-brown zones have relatively high Co, Cu, Ga, As, and Sb; whilst the light-colored zones have relatively high Fe, Mn and Cd. The calculated sphalerite formation temperature based on sphalerite geothermometer – GGIMFis ( Frenzel et al., 2016 ) are basically in agreement with those homogenization temperature of inclusions, indicating that the contents of these elements (Ga, Ge, Fe, Mn and In) in sphalerite are mainly controlled by temperature. Moreover, the estimated sulfur fugacity (log fS2) for Liziping (−14.7) and Fulongchang (−13.6) are distinctly lower than those for Shangnuluo (−7.1) and Baiji (−8.5). Carbonate C–O isotope compositions indicate that the dissolved carbon and oxygen of ore forming-fluids of these Pb-Zn deposits were mainly derived from sedimentary carbonate dissolution. Early-ore-stage molybdenite from Baiji deposit yielded two Re-Os weighted average model ages of 21.4 Ma and 12.93 Ma, and a Re-Os concordia age of 11.88 ± 0.77 Ma was obtained from four younger molybdenite samples. These ages are distinctly younger than those reported mineralization age (ca. 30 Ma) for basinal brine-related Pb-Zn deposits. All these results indicate that there are two different types of Pb-Zn metallogenic events in the northern margin of Lanping Basin.

With new advances in rapid-acquisition geochemical and hyperspectral techniques, exploration companies are now able to detect subtle halos surrounding orebodies at minimal expense. The Nimbus Ag-Zn-(Au) deposit is unique in the Archean Yilgarn Craton of Western Australia. Due to its mineralogy, alteration assemblages, geochemical affinity, and tectonic setting, it is interpreted to represent a shallow water (~650 mbsl) and low-temperature (&lt, 250 °C) volcanogenic massive sulfide (VMS) deposit with epithermal characteristics (i.e., a hybrid bimodal felsic deposit). We present a detailed paragenetic account of the Nimbus deposit, and establish lithogeochemical and hyperspectral halos to mineralization to aid exploration. Mineralization at Nimbus is characterized by early units of barren massive pyrite that replace glassy dacitic lavas, and underlying zones of polymetallic sulfides that replace autoclastic monomict dacite breccias. The latter are dominated by pyrite-sphalerite-galena, a diverse suite of Ag-Sb ± Pb ± As ± (Cu)-bearing sulfosalts, minor pyrrhotite, arsenopyrite, and rare chalcopyrite. The main sulfosalt suite is characterized by pyrargyrite, and Ag-rich varieties of boulangerite, tetrahedrite, and bournonite. Zones of sulfide mineralization in quartz-sericite(±carbonate)-altered dacite are marked by significant mass gains in Fe, S, Zn, Pb, Sb, Ag, As, Cd, Ni, Cu, Ba, Co, Cr, Tl, Bi, and Au. Basaltic rocks show reduced mass gains in most elements, with zones of intense quartz-chlorite-carbonate±fuchsite alteration restricted to thick sequences of hyaloclastite, and near contacts with dacitic rocks. Broad zones of intense silica-sericite alteration surround mineralization in dacite, and are marked by high Alteration Index and Chlorite-Carbonate-Pyrite Index (CCPI) values, strong Na-Ca depletion, and an absence of feldspar (albite) in thermal infrared (TIR) data. White mica compositions are predominantly muscovitic in weakly altered sections of the dacitic footwall sequence. More paragonitic compositions are associated with zones of increased sericitization and high-grade polymetallic sulfide mineralization. Chlorite in dacitic rocks often occurs adjacent to zones of sulfide mineralization and is restricted to narrow intervals. Carbonate abundance is sporadic in dacite, but is most abundant outside the main zones of Na-Ca depletion. Basaltic rocks are characterized by strongly paragonitic white mica compositions, and abundant chlorite and carbonate. Shifts from Ca carbonates and Fe-rich chlorites to more Mg-rich compositions of both minerals occur in more intensely hydrothermally altered basaltic hyaloclastite, and near contacts with dacitic rocks. Hanging-wall polymict conglomerates are characterized by minor amounts of muscovitic to phengitic white mica (2205–2220 nm), and an absence of chlorite and carbonate alteration.

Cumavici is a medium– to low–temperature hydrothermal Sb–Zn–Pb–Ag polymetallic vein–type ore deposit in the Srebrenica orefield, part of the Podrinje Metallogenic District, Eastern Bosnia and Herzegovina. The ore deposit occurs in the form of simple and complex veins along faults and fractures, as well as stockworks and disseminations hosted within Neogene volcanic rocks (pyroclastics and andesite lavas of calc–alkaline affinity). The deposit comprises sulfides (sphalerite, galena, stibnite, pyrite, marcasite, chalcopyrite, arsenopyrite, gudmundite, safflorite, lollingite, gersdorffite and acanthite), sulfosalts (berthierite, geocronite, boulangerite, semseyite, plagionite, jamesonite, bournonite, twinnite, andorite, fizeliyte, Ag–bearing tetrahedrite, stephanite, polybasite, pyrargyrite and argyrodite), native gold and silver, tungstates (hubnerite), oxides, and gangue quartz, chalcedony, Mn–siderite, anglesite, smithsonite, fluorite, gypsum and ludlamite. Three generations of sphalerite are recognized in the Cumavici deposit, evolving from Fe–rich to Fe–poor. The most common are yellowish to colorless Fe–poor varieties. Electron Probe Microanalyses of sphalerite free of micro–inclusions of galena and Pb–Sb-sulfosalts revealed wide compositional variations in minor- and trace–element contents (e.g., Fe, Cd, Mn, Cu, Sn, As, and In). Of particular interest are the lead and antimony content of sphalerite, which vary from 0.10 to 3.08, and 0.02 to 1.62 wt.%, respectively. Lead– and Pb–Sb-rich zones are the most common in sphalerite, while individual Sb–bearing zones are rare. These zones have fan–like forms with circular to wave-like, micron–scale bands, filled with galena or Pb–Sb sulfosalts. In the Pb–Sb zones, the Sb/Pb atomic ratio ranges between 0.3 and 1.5, similar to ratios between geocronite and jamesonite, thus suggesting the presence of micro– to nano–scale inclusion of sulfosalts within the sphalerite. The mean composition of all sphalerite samples is (Zn0.78–0.99,Fe

The Sanjiang Tethyan domain in SE Asia is one of the most important mineral belts in China. Cu, Pb–Zn, Ag, Au and Sn are the most important resources in this domain, while the tungsten mineralization is poorly reported. In this study, we report on mineralogy in recent discovered Damajianshan (DMJS) tungsten (–Cu–As–Mo–Bi) polymetallic deposit in the southern part of Sanjiang Tethyan domain related to Triassic quartz porphyry. Studies have shown that besides common ore minerals, such as native bismuth, bismuthinite, ikunolite, some specific minerals of Pb–Bi- and Pb–Sb-sulphosalts (e.g. izoklakeite, bournonite, cosalite, and boulangerite) have also been found. Based on paragenetic mineral assemblages, fluid inclusions, and thermodynamic studies, the physicochemical conditions were evaluated for the entire metallogenic process. The sulfur fugacity (logf S2 ) ranges from − 9.7 to − 37 with ore-forming temperatures between 190 °C and 330 °C, and the oxygen fugacity (logf O2 ) ranges from − 37.5 to − 38.5 when the temperature is 250 °C. The sulfur fugacity and oxygen fugacity show strong fluctuations with broadly negative correlation, indicating that these variations in physicochemical conditions should be responsible for mineral assemblages, and are one of the most significant factors leading to the formation of the DMJS deposit. Our mineralogical studies provide new information for tungsten mineralization and further exploration of tungsten resources in the Sanjiang Tethyan mineralization domain.

The Malayer-Esfahan Metallogenic Province (MEMP) of western Iran hosts many Pb-Zn deposits and occurrences, largely hosted within a sequence of clastic detrital and carbonate host rocks. A well-known example is Ahangaran which is composed of several hypogene orebodies with estimated resources of ~1.5 Mt sulfide ore grading 4 wt% Pb, 0.5 wt% Zn and 200 g/t Ag, plus a supergene iron-bearing oxyhydroxide ore with 1 Mt reserve and grading 30–35 wt% FeO. The sulfide orebodies are primarily hosted in Lower Cretaceous dolostone and sandstone along the marginal-southern part of the NW–SE trending Kolehbid Syncline. Galena and pyrite, together with chalcopyrite and sphalerite in lesser amounts, comprise the primary sulfide ores. Minor sulfosalt minerals including bournonite, tetrahedrite, freibergite, famatinite and meneghinite have also been identified by electron probe microanalysis. Three paragenetic stages are recognized: (1) pre-sulfide stage (oxide stage); (2) main sulfide stage (including three sulfide sub-stages); and (3) supergene stage. Fluid inclusion studies conducted on pre- and main-sulfide stages identified two end-member fluids: a hot (~290 °C) and saline fluid (~20 wt% NaCl eq.) and a cooler (

Antimony is a common metalloid occurring in the form of Sb-sulfides and sulfosalts, in various base and noble metal deposits. It is also present in corresponding metallurgical products (concentrates) and, although antimony has been considered a penalty element in the past, recently it has gained interest due to its classification as a critical raw material (CRM) by the European Union (EU). In the frame of the present paper, representative ore samples from the main Sb-bearing deposits of Greece (Kilkis prefecture, Chalkidiki prefecture (Kassandra Mines), and Chios Isl.) have been investigated. According to optical microscopy and electron probe microanalysis (EPMA) data, the Greek ores contain stibnite (Sb2S3), boulangerite (Pb5Sb4S11), bournonite (PbCuSbS3), bertherite (FeSbS4), and valentinite (Sb2O3). Bulk analyses by inductively coupled plasma mass spectrometry (ICP-MS) confirmed, for the first time published, the presence of a significant Hg content in the Kilkis Sb-ore. Furthermore, Kassandra Mines ores are found to contain remarkable amounts of Bi, As, Sn, Tl, and Se (excluding Ag, which is a bonus element). The above findings could contribute to potential future exploration and exploitation of Sb ores in Greece.

The medium-sized Zixi gold deposit is hosted in a meta-gabbro–diabase dike, and located geologically in the Xuefengshan belt of the Jiangnan Orogen in South China. Gold-bearing quartz–carbonate–sulfide veins and the ore-hosting meta-gabbro–diabase dike are structurally controlled by the NE-trending first stage faults, which are secondary faults to the regional Xupu–Jingzhou Fault. Metallic minerals at Zixi include arsenopyrite and pyrite, along with minor chalcopyrite, sphalerite, galena, bournonite and native gold. Ore-related alteration includes silicic, carbonate, sericite, and chlorite. Based on vein crosscutting relationships and mineral paragenesis, the alteration/mineralization is divided into three stages: (1) arsenopyrite–pyrite–native gold–quartz mineralization, (2) polymetallic sulfides–native gold–chlorite–carbonate–quartz mineralization, and (3) post-ore carbonate–quartz alteration. To constrain any temporal relationship between the gold mineralization and the ore-hosting meta-gabbro–diabase dike, we obtained a Re–Os isochron age for the gold-bearing arsenopyrite (425 ± 28 Ma, n = 5, MSWD = 0.47), which is 350 Myr younger the meta-gabbro–diabase (zircon U–Pb age: 783.08 ± 0.97 Ma, n = 30, MSWD = 0.39). This precludes the dike from any direct metallogenetic link with the gold deposit. The ore-forming fluids have calculated δ18OH2O and δD values of + 3.5‰ to + 9.1‰ and − 68.1‰ to –55.5‰, respectively, indicating a metamorphic source, probably through dehydration breakdown of chlorite. Sulfur isotope compositions of the gold-bearing pyrite (–5.8‰ to –3.6‰) are distinct from those of the Lengjiaxi Group metamorphic rocks, but marginal overlap with those from the Banxi Group metamorphic rocks. Lead isotope compositions of the gold-bearing pyrite (206Pb/204Pb: 17.08 to 17.63; 207Pb/204Pb: 15.48–15.54; 208Pb/204Pb: 37.64–37.94) suggest that the lead was sourced from metamorphic rocks. The H–O–S–Pb isotopic data indicate that ore-forming materials were derived from a metamorphic source. However, the precise nature of that source is unclear. The Zixi gold mineralization displays many typical features of orogenic gold deposits, such as being structurally controlled, and have similar alteration and mineralization styles, ore mineral assemblages, and H–O–S stable isotopic features. The Zixi gold deposit was likely formed during the early Paleozoic intracontinental orogeny of the Jiangnan Orogen.

Cerromojonite, ideally CuPbBiSe3, represents a new selenide from the El Dragόn mine, Department of Potos&iacute, Bolivia. It either occurs as minute grains (up to 30 &micro, m in size) in interstices of hansblockite/quijarroite intergrowths, forming an angular network-like intersertal texture, or as elongated, thin-tabular crystals (up to 200 &mu, m long and 40 &mu, m wide) within lath-shaped or acicular mineral aggregates (interpreted as pseudomorphs) up to 2 mm in length and 200 &mu, m in width. It is non-fluorescent, black, and opaque, with a metallic luster and black streak. It is brittle, with an irregular fracture, and no obvious cleavage and parting. In plane-polarized incident light, cerromojonite is grey to cream-white, and weakly pleochroic, showing no internal reflections. Between crossed polarizers, cerromojonite is weakly anisotropic, with rotation tints in shades of brown and grey. Lamellar twinning on {110} is common. The reflectance values in air for the COM standard wavelengths (R1 and R2) are: 48.8 and 50.3 (470 nm), 48.2 and 51.8 (546 nm), 47.8 and 52.0 (589 nm), and 47.2 and 52.0 (650 nm). Electron-microprobe analyses yielded a mean composition of: Cu 7.91, Ag 2.35, Hg 7.42, Pb 16.39, Fe 0.04, Ni 0.02, Bi 32.61, Se 33.37, total 100.14 wt %. The empirical formula (based on 6 atoms pfu) is (Cu0.89Hg0.11)&Sigma, = 1.00(Pb0.56Ag0.16Hg0.15 Bi0.11Fe0.01)&Sigma, = 0.99Bi1.00Se3.01. The ideal formula is CuPbBiSe3. Cerromojonite is orthorhombic (space group Pn21m), with a = 8.202(1) &Aring, b = 8.741(1) &Aring, c = 8.029(1) &Aring, V = 575.7(1) &Aring, 3, Z = 4. Calculated density is 7.035 g&middot, cm&minus, 3. The five strongest measured X-ray powder diffraction lines (d in &Aring, (I/I0) (hkl)) are: 3.86 (25) (120), 2.783 (100) (122), 2.727 (55) (212), 2.608 (40) (310), and 1.999 (25) (004). Cerromojonite is a new member of the bournonite group, representing the Se-analogue of součekite, CuPbBi(S,Se)3. It is deposited from strongly oxidizing low-T hydrothermal fluids at a fSe2/fS2 ratio &gt, 1, both as primary and secondary phase. The new species has been approved by the IMA-CNMNC (2018-040) and is named for Cerro Mojon, the highest mountain peak closest to the El Drag&oacute, n mine.

Although native bismuth is a relatively common mineral, native antimony is less abundant, and Sb-Bi alloys are relatively rare phases in Nature. Sb-Bi alloys and Ag-Cu-Pb-Sb-Bi sulphosalts have been discovered in the Jialong vein-type Cu-Sn deposit in North Guangxi, South China. The Jialong deposit is hosted by schist within the contact zone of a Neoproterozoic granite. Four stages of ore formation are recognised, with the Sb-Bi alloy- and sulphosalt-bearing assemblage formed during the third stage. Sulphosalts include Pb-Bi-Ag sulphosalts (pavonite), Sb-Bi sulphosalts (tintinaite, terrywallaceite), and Sb sulphosalt (ullmanite, freibergite, bournonite). Grains of Sb-Bi alloy measure 2–20 μm in diameter, show rounded margins and occur together with galena along the edges or internal fissures of sulphosalts. The Sb-Bi alloys do not coexist with bismuthinite, BiS (an unnamed mineral), or with native bismuth. Two phases of Sb-Bi alloys are identified based on back-scattered electron image observations and electron microprobe analysis. The textural and thermodynamic relationships indicate that Phase I was formed before Phase II. Phase I contains high Sb (69.15–80.12 wt %) and lower Bi (18.01–27.85 wt %), while Phase II contains low Sb (0.89–25.24 wt %) and high Bi (72.95–98.89 wt %). Cooling in the range of 270–400 °C and decreasing sulphur fugacity promote precipitation of Sb-Bi alloys and sulphosalts during the late stage of incursion of Sb- and Bi-bearing magmatic hydrothermal fluids.

Baiyangping Pb–Zn–Cu–Ag deposit is located in Lanping basin, northwestern Yunnan province. The deposit is composed of a few ore veins and can be divided into several ore blocks. The ore bodies are primarily hosted in Mesozoic carbonate, sandstone and siltstone along the north–south-striking, NWW-striking and NE–SW-striking fault zones. There are breccia, massive, vein like and disseminated ores. The main ore minerals are sphalerite, galena, gratonite, jordanite, tetrahedrite series minerals, chalcocite, chalcopyrite, realgar, orpiment, bournonite, cobalt-bearing arsenopyrite, argentite, kongsbergite, cobaltine, siegenite. The sizes of fluid inclusions in Baiyangping deposit are generally less than 10 μm and have the shape of round, oval, irregular, etc. The ore-forming fluid system is Ca 2+ –Na + –K + –Mg 2+ –Cl − –F − –NO 3 − brine system. The freezing temperature of fluid inclusions in mineral deposits ranges from −26.4 to −0.2 °C, average −14.6 °C; the homogenization temperature is concentrated in 120–180 °C, and the salinity is between 0.35 and 24.73 wt% (NaCl eq ), average 16.9 wt% (NaCl eq ). δ 13 C PDB and δ 18 O SMOW values of hydrothermal calcite range from −4.16‰ to 3‰ and −2.5‰ to 20.4‰, respectively. δ 34 S values of sulfide minerals range from −10.2‰ to 11.2‰, average 5.6‰. The sulfide samples yield 206 Pb/ 204 Pb values of 18.609–18.818, 207 Pb/ 204 Pb of 15.548–15.842 and 208 Pb/ 204 Pb = 38.514–39.556. C–O–S–Pb isotope compositions of the Baiyangping deposit indicate a homogeneous carbon source, and the carbon in hydrothermal calcite is derived from the dissolution of carbonate rock strata, the ore-forming fluid belongs to basin brine fluid system, which is mixed with the precipitate water, sulfur in sulfides and sulfosalts is derived from thermal chemical sulfate reduction, and the thermal decomposition of sulfur-bearing organic matter. The metal mineralization material is from sedimentary strata and basement. The late Pb–Zn polymetallic mineralization event superposed within early Cu–Co polymetallic mineralization event resulted in the differences of ore-forming elements for Baiyangping deposit.

The Rockliden massive sulphide Zn–Cu deposit contains minor amounts of Sb minerals. The Sb mineralogy is complex in terms of composition, micro textures and mineral associations. The main Sb minerals comprise tetrahedrite, bournonite, gudmundite and Sb–Pb sulphides such as meneghinite. The presence of these minerals is especially critical to the quality of the Cu–Pb concentrate. To study how they are distributed in a simplified flotation circuit and what controls their process behaviour Sb-rich drill core samples were selected from the Rockliden deposit and a standard laboratory flotation test was run on the composite samples. Scanning electron microscope-based automated mineralogy was used to measure the Sb mineralogy of the test products, and the particle tracking technique was applied to mass balance the different liberation classes to finally trace the distribution of liberated and locked Sb minerals. The mineralogical factors controlling the distribution of Sb minerals are mineral grain size, the degree of liberation, and associated minerals. Similarities in the distribution of specific particle types from the tested composites point towards systematics in the behaviour of particles and predictability of their distribution which is suggested to be used in a geometallurgical model of the deposit.

Mineral assemblages and chemical compositions of ore minerals from the Boroo gold deposit in the North Khentei gold belt of Mongolia were studied to characterize the gold mineralization, and to clarify crystallization processes of the ore minerals. The gold deposit consists of low-grade disseminated and stockwork ores in granite, metasedimentary rocks and diorite dikes. Moderate to high-grade auriferous quartz vein ores are present in the above lithological units. The ore grades of the former range from about 1 to 3 g/t, and those of the latter from 5 to 10 g/t, or more than 10 g/t Au. The main sulfide minerals in the ores are pyrite and arsenopyrite, both of which are divisible into two different stages (pyrite-I and pyrite-II; arsenopyrite-I and arsenopyrite-II). Sphalerite, galena, chalcopyrite, and tetrahedrite are minor associated minerals, with trace amounts of bournonite, boulangerite, geerite, alloclasite, native gold, and electrum. The ore minerals in the both types of ores are variable in distribution, abundance and grain size. Four modes of gold occurrence are recognized: (i) “invisible” gold in pyrite and arsenopyrite in the disseminated and stockwork ores, and in auriferous quartz vein ores; (ii) microscopic native gold, 3 to 100 µm in diameter, that occurs as fine grains or as an interstitial phase in sulfides in the disseminated and stockwork ores, and in auriferous quartz vein ores; (iii) visible native gold, up to 1 cm in diameter, in the auriferous quartz vein ores; and (iv) electrum in the auriferous quartz vein ores. The gold mineralization of the disseminated and stockwork ores consists of four stages characterized by the mineral assemblages of: (i) pyrite-I + arsenopyrite-I; (ii) pyrite-II + arsenopyrite-II; (iii) sphalerite + galena + chalcopyrite + tetrahedrite + bournonite + boulangerite + alloclasite + native gold; and (iv) native gold. In the auriferous quartz vein ores, five mineralization stages are defined by the following mineral assemblages: (i) pyrite-I; (ii) pyrite-II + arsenopyrite; (iii) sphalerite + galena + chalcopyrite; (iv) Ag-rich tetrahedrite-tennantite + bournonite + geerite + native gold; and (v) electrum. The As–Au relations in pyrite-II and arsenopyrite suggest that gold detected as invisible gold is mostly attributed to Au+1 in those minerals. By applying the arsenopyrite geothermometer to arsenopyrite-II in the disseminated and stockwork ores, crystallization temperature and logfs2 are estimated to be 365 to 300 °C and –7.5 to –10.1, respectively.

An understanding of the structural features and bonding of a particular material, and the properties these features impart on its physical characteristics, is essential in the search for new systems that are of technological interest. For several relevant applications, the design or discovery of low thermal conductivity materials is of great importance. We report on the synthesis, crystal structure, thermal conductivity, and electronic-structure calculations of one such material, PbCuSbS3 . Our analysis is presented in terms of a comparative study with Sb2 S3 , from which PbCuSbS3 can be derived through cation substitution. The measured low thermal conductivity of PbCuSbS3 is explained by the distortive environment of the Pb and Sb atoms from the stereochemically active lone-pair s(2) electrons and their pronounced repulsive interaction. Our investigation suggests a general approach for the design of materials for phase-change-memory, thermal-barrier, thermal-rectification and thermoelectric applications, as well as other functions for which low thermal conductivity is purposefully sought.

The Arcos deposit is located in the NW of the Iberian Variscan Massif, and consists of a pollymetallic Au–As (Ag–Pb–Zn–Cu–Sb) vein-disseminated mineralization. It is temporally and spatially related to post-Variscan rhyolite dikes and structurally controlled by Late-Variscan and Variscan structures. The mineralization in Arcos is divided into two stages. The first (Au–As) consists of fine-grained Au-bearing pyrite and arsenopyrite, with Au occurring as invisible gold. Sulfides occur filling veins as well as disseminated in hydrothermally altered (silicification, dolomitization, phyllic alteration and sulfidation) rhyolites and impure limestones and calcareous slates, Lower Cambrian in age. Several types of pyrite and arsenopyrite are defined according to their chemical and textural characteristics. Among these, the Py-II and Apy-II types are Au-bearing. Py-II is As-rich (up to 5 wt.%) and is the main Au-bearing mineral (up to 0.2 wt.% of Au) in Arcos, while Au content in Apy-II is local and low (up to 0.03 wt.% of Au). The Py-II occurs as fine-grained pyritohedra and overgrowth rims of previous pyrite crystals, showing oscillatory As-zoning. The highest Au-contents are in the As-richer zones. The Au/As ratios of Py-II and Apy-II indicate that Au was mainly deposited as solid solution, suggesting that they precipitated from fluids undersaturated in Au. Sulfidation of iron derived from the alteration of ferroan silicates (mainly biotite) was the most important depositional mechanism of invisible gold in Arcos. The second stage of mineralization shows an Ag–Pb–Zn–Cu–Sb metallic signature. It replaces the first stage and consists of sphalerite, Ag-bearing tetrahedrite, bournonite, chalcopyrite and galena with Bi–Pb–Sb sulfosalts, pyrrhotite, Ni–Co–Fe sulfides and electrum as accessory minerals. The gangue minerals of this stage include Ca–Mg–Fe carbonates, quartz with minor fluorite and chlorite. In the most superficial levels of the area, secondary native Au, covellite and Fe oxide and hydroxide developed due to oxidation of the ore. The vein-disseminated mineralization of Arcos represents a distal deposit of an intrusion-related gold system developed around an unexposed, post-Variscan, calc-alkaline granitoid in the NW Iberian Massif.

To build on the success of other mineral systems employed in solar cells, including kesterites (Cu2ZnSnS4) and herzenbergite (SnS), as well as mineral-inspired systems such as lead halide perovskites (CH3NH3PbI3), we have searched for photoactive minerals with the additional constraint that a polar crystal structure is adopted. Macroscopic electric fields provide a driving force to separate electrons and holes in semiconductor devices, while spontaneous lattice polarisation in polar semiconductors can facilitate microscopic photo-carrier separation to enhance carrier stability and lifetimes. We identify enargite (Cu3AsS4), stephanite (Ag5SbS4), and bournonite (CuPbSbS3) as candidate materials and explore their chemical bonding and physical properties using a first-principles quantum mechanical approach.

© the Owner Societies 2017. Bournonite (CuPbSbS3) is an earth-abundant mineral with potential thermoelectric applications. This material has a complex crystal structure (space group Pmn21#31) and has previously been measured to exhibit a very low thermal conductivity (κ < 1 W m-1K-1at T ≥ 300 K). In this study, we employ high-throughput density functional theory calculations to investigate how the properties of the bournonite crystal structure change with elemental substitutions. Specifically, we compute the stability and electronic properties of 320 structures generated via substitutions {Na-K-Cu-Ag}{Si-Ge-Sn-Pb}{N-P-As-Sb-Bi}{O-S-Se-Te} in the ABCD3formula. We perform two types of transport calculations: the BoltzTraP model, which has been extensively tested, and a newer AMSET model that we have developed and which incorporates scattering effects. We discuss the differences in the model results, finding qualitative agreement except in the case of degenerate bands. Based on our calculations, we identify p-type CuPbSbSe3, CuSnSbSe3and CuPbAsSe3as potentially promising materials for further investigation. We additionally calculate the defect properties, finding that n-type behavior in bournonite and the selected materials is highly unlikely, and p-type behavior might be enhanced by employing Sb-poor synthesis conditions to prevent the formation of SbPbdefects. Finally, we discuss the origins of various trends with chemical substitution, including the possible role of stereochemically active lone pair effects in stabilizing the bournonite structure and the effect of cation and anion selection on the calculated band gap.

Identification of silver-rich sulfide mineralization in the abandoned mines at northern Hymittos Mt (central Attica, Greece) district has made this region important due to its structural relation to the world-class Lavrion mining district (25 km SE of Hymittos Mt.). At Agios Ioannis Kynigos mine veins of oxidized Fe-Pb-Zn-Ag ore are hosted in mylonitic marbles that were predominantly affected by brittle-ductile deformation associated with the West Cycladic Detachment System. The major sulfides are galena and arsenian pyrite which develop as open-space filling (fractures and vugs), disseminations and veinlets. Galena contains abundant inclusions of Pb-As-Sb-Cu-Ag sulfosalts (tetrahedrite group minerals, bournonite, jalpaite). An unusual silver-rich galena ore i.e from 192 to 1500 ppm Ag, is recorded from the present study, with Ag hosted mainly in Ag-tetrahedrite, acanthite and jalpaite. Compositionally pyrite shows As enrichment and the highest As concentration i.e. up to 3.9 wt% is found in the core of the oscillatory zoned pyrites. Values of δ34S of galena are isotopically light (−11.2 to −12.2‰), which suggests a sedimentary component to the ore fluid, that is likely derived from leaching of the meta-sedimentary (calc-mica schists) wall rocks. Carbon and oxygen isotope compositions of ore-stage carbonates show values i.e δ13CV-PDB (‰) = −8.2 to −11.7‰ and δ18O = 24.3 to 25.9‰ and for the non-mineralized carbonates δ13CV-PDB (‰) = +0.33 to 2.52‰ and δ18O = 20.8 to 26.1‰. The C and O isotopic composition of the carbonate wall rock distal to the orebody is typical of marine carbonates, whereas hydrothermal carbonates (brown calcite and dolomite) are dominated by an external, light C source. The lowest δ13CV-PDB values are recorded from cerussite and correspond to the low temperature supergene alteration from meteoric waters. The homogenized values of δ18O in the mineralized carbonates indicate interaction of fluid with host carbonates under a low fluid/rock ratio. The Pb-Zn-Ag mineralization at Agios Ioannis Kynigos bears many similarities with the low-temperature carbonate replacement-style mineralization in Kamariza, Lavrion area. Ore deposition in the northern Hymittos detachment fault is focused in the structurally upper parts of the detachment fault where circulation of meteoric fluids is dominant in the hydrothermal system.

The photoelectrochemical performance of six naturally occurring semiconducting sulfide minerals is investigated to simply and quickly evaluate their photovoltaic potential. The direct optical band gaps determined for these minerals are 1.36 eV for Enargite, 1.40 eV for Chalcostibite, 1.67 eV for Stephanite, 1.29 eV for Bournonite, 1.43 eV for Jamesonite and 1.66 eV for Gratonite, all in the range of usefulness for single or multijunction solar cells.

CuPbSbS3-bournonite is a quaternary semiconductor derived from the Cuâ?Sbâ?S semiconductors with numerous possibilities including optoelectronic and photovoltaic applications. An analysis focusing on the potential for solar cells is carried out starting from first-principles density functional theory with orbital-dependent one-electron potentials. In order to understand the fundamental factors responsible for the absorption, the absorption coefficients have been split into inter- and intra-species contributions. The absorption coefficients are used as a criterion for evaluating the efficiencies when this material is used to absorb sunlight at several concentrations. The results indicate their applicability in photovoltaic devices as absorbent of the solar spectrum with high energy conversion efficiency.

Quijarroite, ideally Cu6HgPb2Bi4Se12, is a new selenide species from the El Dragόn mine, Department of Potosí, Bolivia. It most frequently occurs as lath-shaped thin plates (up to 150 µm in length and 20 µm in width) intimately (subparallel) intergrown with hansblockite, forming an angular network-like intersertal texture. Quijarroite is occasionally also present as sub- to anhedral grains up to 200 µm in length and 50 µm in width. It is non-fluorescent, black and opaque with a metallic luster and black streak. It is brittle, with an irregular fracture and no obvious cleavage and parting. In plane-polarized incident light, quijarroite is weakly pleochroic from cream to very slightly more brownish-cream, displaying no internal reflections. Between crossed polars, quijarroite is moderately anisotropic with pale orange-brown to blue rotation tints. Lamellar twinning on {110} is common; parquet twinning occurs rarely. The reflectance values in the air for the COM (Commission on Ore Mineralogy) standard wavelengths (R1 and R2) are: 46.7, 46.8 (470 nm), 47.4, 48.2 (546 nm), 47.1, 48.5 (589 nm), and 46.6, 48.7 (650 nm). Electron-microprobe analyses yielded a mean composition of Cu 13.34, Ag 1.02, Hg 7.67, Pb 16.87, Co 0.03, Ni 0.15, Bi 27.65, Se 33.52, total 100.24 wt %. The mean empirical formula, normalized to 25 apfu (atoms per formula unit), is (Cu5.84Ag0.26)Σ = 6.10(Hg1.06Ni0.07Co0.01)Σ = 1.14Pb2.27Bi3.68Se11.81 (n = 24). The simplified formula is Cu6HgPb2Bi4Se12. Quijarroite is orthorhombic, space group Pmn21, with a = 9.2413(8), b = 9.0206(7), c = 9.6219(8) Å, V = 802.1(1) Å3, Z = 1. The calculated density is 5.771 g·cm−3. The five strongest X-ray powder-diffraction lines (d in Å (I/I0) (hkl)) are: 5.36 (55) (111), 3.785 (60) (211), 3.291 (90) (022), 3.125 (100) (212), and 2.312 (50) (400). The crystal structure of quijarroite can be considered a galena derivative and could be derived from that of bournonite. It is a primary mineral, deposited from an oxidizing low-T hydrothermal fluid at a f S e 2 / f S 2 ratio greater than unity. The new species has been approved by the IMA-CNMNC (2016-052) and is named for the Quijarro Province in Bolivia, in which the El Dragón mine is located.