Gra ianite, MnBi2S4, a new mineral from the Baia Bihor skarn, Romania

Ciobanu, Cristiana L.; Brugger, Joël; Cook, Nigel J.; Mills, Stuart J.; Elliott, Peter; Damian, Gheorghe; Damian, Floarea

doi:10.2138/am.2014.4836

Cited by 14 publications

(10 citation statements)

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“…The technological revolution outlined above has accelerated the search for, and characterization of new ore minerals, particularly in cases where the phase in question is only a few microns in size and intergrown with other related phases. For example, FIB-SEM was successfully used to extract tiny samples of the new mineral graţianite for structural study [185]. Hazen et al (2017) [186] have recently made a convincing case for the acknowledgement, as "anthropogenic minerals", of compounds that originate from human action.…”

Section: Discovery Of New Mineralsmentioning

confidence: 99%

Advances and Opportunities in Ore Mineralogy

et al. 2017

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Abstract:The study of ore minerals is rapidly transforming due to an explosion of new microand nano-analytical technologies. These advanced microbeam techniques can expose the physical and chemical character of ore minerals at ever-better spatial resolution and analytical precision. The insights that can be obtained from ten of today's most important, or emerging, techniques and methodologies are reviewed: laser-ablation inductively-coupled plasma mass spectrometry; focussed ion beam-scanning electron microscopy; high-angle annular dark field scanning transmission electron microscopy; electron back-scatter diffraction; synchrotron X-ray fluorescence mapping; automated mineral analysis (Quantitative Evaluation of Mineralogy via Scanning Electron Microscopy and Mineral Liberation Analysis); nanoscale secondary ion mass spectrometry; atom probe tomography; radioisotope geochronology using ore minerals; and, non-traditional stable isotopes. Many of these technical advances cut across conceptual boundaries between mineralogy and geochemistry and require an in-depth knowledge of the material that is being analysed. These technological advances are accompanied by changing approaches to ore mineralogy: the increased focus on trace element distributions; the challenges offered by nanoscale characterisation; and the recognition of the critical petrogenetic information in gangue minerals, and, thus the need to for a holistic approach to the characterization of mineral assemblages. Using original examples, with an emphasis on iron oxide-copper-gold deposits, we show how increased analytical capabilities, particularly imaging and chemical mapping at the nanoscale, offer the potential to resolve outstanding questions in ore mineralogy. Broad regional or deposit-scale genetic models can be validated or refuted by careful analysis at the smallest scales of observation. As the volume of information at different scales of observation expands, the level of complexity that is revealed will increase, in turn generating additional research questions. Topics that are likely to be a focus of breakthrough research over the coming decades include, understanding atomic-scale distributions of metals and the role of nanoparticles, as well how minerals adapt, at the lattice-scale, to changing physicochemical conditions. Most importantly, the complementary use of advanced microbeam techniques allows for information of different types and levels of quantification on the same materials to be correlated.

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Section: Discovery Of New Mineralsmentioning

confidence: 99%

Advances and Opportunities in Ore Mineralogy

et al. 2017

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“…Baita Bihor is an unusually Bi-rich skarn deposit, and the type locality for several rare sulphosalts, including paderaite [99], cupromakovickyite [100], cuproneyite [76], and recently, also gratianite [14]. Skarn deposits worldwide show a close relationship between Bi-minerals and gold (e.g., [101]).…”

Section: Discussionmentioning

confidence: 99%

“…The study was carried out on samples from a massive assemblage comprised of different bismuth sulphosalts and galena collected from the deeper part of the Antoniu North Cu orepipe, one of several that make up the Baita Bihor Cu-Mo-Zn-Pb skarn deposit, in Romania [88]. Metal zonation in the Baita Bihor orefield [89] is superimposed by Au-(Ag)-richer ores closely associated with bismuth sulphosalts, lending the otherwise dominant Cu (Mo) orebodies a more polymetallic character [7,14,76]. Previous LA-ICP-MS study of this assemblage (Figure 2a) has shown wide variation in the concentration of Au measured in sulphosalts on either side of a boundary defining changes in sulphosalt speciation (from a few to several thousand ppm [90]).…”

Section: Case Studymentioning

confidence: 99%

“…In-situ extraction of small volumes of sample material by FIB-SEM has also proven valuable for the characterization of new minerals (e.g., in the case of gratianite [14]). Using microbeam X-Ray synchrotron source spectrometry, such an approach can be applied for crystal-structural characterization where the phase of interest is both fine-grained and intergrown with other minerals of similar composition and/or structure.…”

Section: Introductionmentioning

confidence: 99%

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Focused Ion Beam and Advanced Electron Microscopy for Minerals: Insights and Outlook from Bismuth Sulphosalts

et al. 2016

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This paper comprises a review of the rapidly expanding application of nanoscale mineral characterization methodology to the study of ore deposits. Utilising bismuth sulphosalt minerals from a reaction front in a skarn assemblage as an example, we illustrate how a complex problem in ore petrology, can be approached at scales down to that of single atoms. We demonstrate the interpretive opportunities that can be realised by doing this for other minerals within their petrogenetic contexts. From an area defined as Au-rich within a sulphosalt-sulphide assemblage, and using samples prepared on a Focused Ion Beam-Scanning Electron Microscopy (SEM) platform, we identify mineral species and trace the evolution of their intergrowths down to the atomic scale. Our approach progresses from a petrographic and trace element study of a larger polished block, to high-resolution Transmission Electron Microscopy (TEM) and High Angle Annular Dark Field (HAADF) Scanning-TEM (STEM) studies. Lattice-scale heterogeneity imaged in HAADF STEM mode is expressed by changes in composition of unit cell slabs followed by nanoparticle formation and their growth into "veins". We report a progressive transition from sulphosalt species which host lattice-bound Au (neyite, lillianite homologues; Pb-Bi-sulphosalts), to those that cannot accept Au (aikinite). This transition acts as a crystal structural barrier for Au. Fine particles of native gold track this progression over the scale of several hundred microns, leading to Au enrichment at the reaction front defined by an increase in the Cu gradient (several wt %), and abrupt changes in sulphosalt speciation from Pb-Bi-sulphosalts to aikinite. Atom-scale resolution imaging in HAADF STEM mode allows for the direct visualisation of the three component slabs in the neyite crystal structure, one of the largest and complex sulphosalts of boxwork-type. We show for the first time the presence of aikinite nanoparticles a few nanometres in size, occurring on distinct (111) PbS slabs in the neyite. This directly explains the non-stoichiometry of this phase, particularly with respect to Cu. Such non-stoichiometry is discussed elsewhere as defining distinct mineral species. The interplay between modular crystal structures and trace element behaviour, as discussed here for Au and Cu, has applications for other mineral systems. These include the incorporation and release of critical metals in sulphides, heavy elements (U, Pb, W) in iron oxides, the distribution of rare earth elements (REE), Y, and chalcophile elements (Mo, As) in calcic garnets, and the identification of nanometre-sized particles containing daughter products of radioactive decay in ores, concentrates, and tailings.

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“…x/a y/b z/c U eq Sb1 0.70359(5) 1 0.38410(4) 0.0260(2) *As2/As2' 0.45606(11) ½ 0.20441(8) 0.0329(5) *Mn2/Mn2' ½ 0 0 0.0384(7) *As3/As3' 0.23266(10) 0 0.11593(9) 0.0383 5 Luboržákite is only the second member of the series having Mn as a species-defining cation after graţianite MnBi 2 S 4 (N = 3) (Ciobanu et al, 2014). The synthetic monoclinic modification of MnSb 2 S 4 (Pfitzner and Kurowski, 2000) is the homologue N = 2 ( 2 P), with Mn in both layer types which, accidentally, are almost identical in 2 P but still preserve some differences.…”

Section: Atommentioning

confidence: 99%

Luboržákite, Mn₂AsSbS₅, a new member of pavonite homologous series from Vorontsovskoe gold deposit, Northern Urals, Russia

Kasatkin

Makovicky

Plášil

et al. 2020

MinMag

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Luboržákite, ideally Mn2AsSbS5, is a new mineral from the Vorontsovskoe gold deposit, Northern Urals, Russia. It forms long-prismatic crystals up to 70 × 20 μm and anhedral grains of the same size embedded in the matrix of Mn-bearing dolomite and Mn-bearing calcite. Associated minerals include pyrite, orpiment, realgar, stibnite, aktashite, alabandite, boscardinite, chabournéite, coloradoite, clerite, écrinsite, gold, routhierite, sphalerite and twinnite. Luboržákite is black, opaque with metallic lustre and has a black streak. It is brittle and has an uneven fracture. No cleavage and parting have been observed. Mohs hardness is 4–4½. Dcalc = 4.181 g cm–3. In reflected light, luboržákite is tin-white, weakly anisotropic with rotation tints varying from dark grey to grey. The chemical composition of luboržákite is (wt.%; electron microprobe, WDS mode): Mn 21.23, Cu 0.29, Ag 0.56, Pb 1.90, As 15.25, Sb 27.03, S 33.23, total 99.49. The empirical formula based on the sum of all atoms = 9 apfu is Mn1.86Pb0.04Ag0.03Cu0.02As0.98Sb1.07S5.00. The new mineral is monoclinic, space group C2/m with a = 12.5077(6), b = 3.8034(2), c = 16.0517(8) Å, β = 94.190(4)°, V = 761.57(6) Å3 and Z = 4. The crystal structure of luboržákite was solved from the single-crystal X-ray diffraction data to R = 0.0383 for 712 observed reflections with I > 3σ(I). Luboržákite is a new member of the heterochemical isostructural series of ‘unit-cell twinned’ structures, named the pavonite series. The new mineral honours Lubor Žák, a prominent Czech crystallographer and the professor of the Charles University in Prague, Czech Republic.

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Gra ianite, MnBi2S4, a new mineral from the Baia Bihor skarn, Romania

Cited by 14 publications

References 32 publications

Advances and Opportunities in Ore Mineralogy

Advances and Opportunities in Ore Mineralogy

Focused Ion Beam and Advanced Electron Microscopy for Minerals: Insights and Outlook from Bismuth Sulphosalts

Luboržákite, Mn₂AsSbS₅, a new member of pavonite homologous series from Vorontsovskoe gold deposit, Northern Urals, Russia

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Gra ianite, MnBi2S4, a new mineral from the Baia Bihor skarn, Romania

Cited by 14 publications

References 32 publications

Advances and Opportunities in Ore Mineralogy

Advances and Opportunities in Ore Mineralogy

Focused Ion Beam and Advanced Electron Microscopy for Minerals: Insights and Outlook from Bismuth Sulphosalts

Luboržákite, Mn2AsSbS5, a new member of pavonite homologous series from Vorontsovskoe gold deposit, Northern Urals, Russia

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Luboržákite, Mn₂AsSbS₅, a new member of pavonite homologous series from Vorontsovskoe gold deposit, Northern Urals, Russia