The Canadian Journal of Mineralogy and Petrology最新文献

{"title":"Murphyite, Pb(TeO)4, the Te-Analogue of Raspite, a New Mineral from Tombstone, Arizona, USA","authors":"Hexiong Yang, X. Gu, R. Gibbs, R. Downs","doi":"10.3749/2200064","DOIUrl":"https://doi.org/10.3749/2200064","url":null,"abstract":"\u0000 A new mineral species, murphyite (IMA 2021-107), ideally Pb(TeO4), has been found from the Grand Central mine, Tombstone, Arizona, USA. It occurs as bladed or prismatic crystals on top of a quartz matrix. Associated minerals include chlorargyrite, emmonsite, ottoite, stolzite, scheelite, schieffelinite, quartz, and jarosite. Individual crystals of murphyite are up to 0.20 × 0.05 × 0.05 mm in size. Twinning is common on {100}. Murphyite is colorless to very pale yellow in transmitted light, transparent with white streak and adamantine luster. It is brittle and has a Mohs hardness of ∼3½, with perfect cleavage on {100}. The calculated density is 7.579 g/cm3. Murphyite is insoluble in water or hydrochloric acid. An electron microprobe analysis yielded the empirical formula (based on 4 O apfu): (Pb0.96Fe0.03Mn0.02)Σ1.01[(Te0.61W0.38)Σ0.99O4], which can be simplified to Pb[(Te,W)O4].\u0000 Murphyite is the Te-analogue of raspite, Pb(WO4), and represents the first mineral with Te6+ substituting for W6+ over 50%. It is monoclinic with space group P21/a and unit-cell parameters a = 13.6089(3), b = 5.01750(10), c = 5.5767(2) Å, β = 107.9280(10)°, V = 362.302(17) Å3, and Z = 4. Its crystal structure consists of distorted MO6 (M = Te + W) octahedra sharing edges to form zigzag chains running parallel to [010]. These chains are linked together by PbO7 polyhedra. Compared to raspite, the substitution of W6+ by Te6+, which has a smaller ionic radius, results in a noticeable structural change: a significant decrease in MO6 octahedral angle distortion, with a concomitant increase in both MO6 octahedral volume and average Pb–O bond length. The unit-cell volume increases from 358.72(4) Å3 for raspite to 362.302(17) Å3 for murphyite. Raman spectroscopic data show that the major peak ascribable to M–O symmetrical stretching vibrations within the MO6 octahedron is centered at 870 cm−1 for raspite but at 881 cm−1 for murphyite.","PeriodicalId":218967,"journal":{"name":"The Canadian Journal of Mineralogy and Petrology","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132256258","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Melansonite, (Na,□)□2KZrSi8O19·5H2O, a New Member of the Rhodesite Group, from Mont Saint-Hilaire, Québec, Canada: Characterization, Crystal-Structure Determination, and Origin","authors":"Thomas E. Gore, A. McDonald","doi":"10.3749/2000114","DOIUrl":"https://doi.org/10.3749/2000114","url":null,"abstract":"\u0000 Melansonite, ideally (Na,□)□2KZrSi8O19·5H2O, is a new mineral discovered at the Poudrette Quarry, Mont Saint-Hilaire, Québec, Canada. It develops as loose clusters of square to rectangular, euhedral plates with average dimensions of 35 × 50 μm. Individual crystals are ∼2 μm in thickness, dominated by the pinacoid {100}, and colorless to pale yellow in color. Associated minerals include albite, calcite, aegirine, quartz, gaidonnayite, a sodic clinoamphibole, an apophyllite-group mineral, and pyrrhotite (?). Melansonite has a vitreous luster, is transparent, and has a white streak. It exhibits a perfect {100} cleavage, is brittle, and has an irregular fracture. The mineral shows a green fluorescence under short-wave radiation. The calculated density is 2.352 g/cm3. Optically, it is non-pleochroic and presumed to be optically biaxial, with α = 1.536(1), β = 1.537(1), γ = 1.538(1) (for λ = 590 nm), 2Vcalc = 89.9(1)°. No dispersion was noted. The optical orientation is inferred to be Z = b, Y = c, Z = a, based on the observed symmetry and crystal morphology. An average of 15 electron microprobe analyses gave Na2O 2.82, Al2O3 6.32, SiO2 53.50, SO3 0.91, K2O 2.64, CaO 1.75, MnO 1.09, Fe2O3 0.46, Y2O3 0.07, ZrO2 15.41, BaO 1.35, H2O (calc.) 11.32, total 97.64 wt.%. The empirical formula (based on 24 anions) is: (Na0.63Ca0.25Mn0.12)Σ1.00(□1.91Na0.09)Σ2.00(□0.48K0.45Ba0.07)Σ1.00(Zr0.99Fe0.05Y0.01)Σ1.05(Si7.08Al0.99S0.09)Σ8.16O19·5H2O. The mineral is orthorhombic, crystallizing in the space group Pmma (No. 51), with a = 24.063(5), b = 6.9820(14), c = 6.5260(13) Å, V = 1096.4(4) Å3, Z = 2. The strongest six lines of the X-ray powder-diffraction pattern [d in Å (I) (hkl)] are 11.988 (100) (200), 3.060 (29) (121), 6.971 (27) (010), 2.881 (25) (321), 6.529 (19) (001), 3.429 (15) (601). A Raman spectrum is presented; it is very similar to that of monteregianite-(Y), with shifts between the two minerals being consistent with Zr ↔ Y substitution. The crystal structure was refined to R = 5.39%, wR2 = 15.45%. It is strongly layered, with a motif based on double sheets of tetrahedra (T), single sheets of octahedra (O), and extra-framework cations. Double layers of tetrahedra (T) are composed of both eight- and four-membered rings of corner-sharing (Si,Al)O4 tetrahedra that form infinite sheets on (100). Individual layers of the double sheet are joined via branching Si(2) tetrahedra along [100]. Channels created by eight-membered rings of (Si,Al)O4 tetrahedra are occupied by Na, K, and H2O groups. The O layers are composed of edge-sharing Mϕ6 (M = Zr, Na, ϕ = O2−, H2O) octahedra that form infinite sheets on (001). Alternating T and O layers give rise to a TOT topology reminiscent of that observed in micas and characteristic of minerals, including rhodesite, delhayelite, hydrodelhayelite, and monteregianite-(Y), with which melansonite shares a crystal-chemical relationship. Melansonite is paragenetically a late-stage mineral that is considered to have formed as a res","PeriodicalId":218967,"journal":{"name":"The Canadian Journal of Mineralogy and Petrology","volume":"92 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122443629","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hydrothermal Pentlandite (Ni,Fe)9S8 from Kambalda, Western Australia: Occurrences, Formation Conditions, and Association with Orogenic Gold","authors":"S. Staude, M. Scharrer, G. Markl, I. Simon, K. Pfaff, T. Monecke, P. Blanc","doi":"10.3749/2200032","DOIUrl":"https://doi.org/10.3749/2200032","url":null,"abstract":"\u0000 Pentlandite, (Ni,Fe)9S8, most commonly occurs in mafic or ultramafic rocks in association with other sulfide minerals, including pyrrhotite and chalcopyrite. However, at a few localities pentlandite has been found in hydrothermal settings. At Kambalda in Western Australia, hydrothermal pentlandite occurs in three different vein types: (1) sulfide veins, (2) quartz-calcite veins associated with biotite-epidote alteration, and (3) calcite veins containing arsenides and base metal sulfide minerals. In all three vein types, pentlandite (1) is restricted to veins crosscutting magmatic Ni sulfide lenses, (2) only occurs within <10 m of sulfide bodies, and (3) is associated only with pyrrhotite.\u0000 In some cases, the pentlandite in the hydrothermal veins has higher Fe and lower Co contents compared to that in the magmatic Ni sulfide ores. The sulfarsenide minerals also show a bimodal distribution in terms of their chemistry: those associated with hydrothermal veins are dominated by Ni, whereas those associated with a primary magmatic origin are rich in Co. Intermediate compositions are observed, notably where hydrothermal sulfarsenide minerals directly overgrow earlier magmatic sulfide minerals.\u0000 Thermodynamic calculations show that the hydrothermal pentlandite-pyrrhotite assemblages can form from highly reduced, hydrothermal fluids at near neutral pH. Pentlandite deposition can be triggered by an increase in pH and/or a decrease in temperature. Associated gangue minerals, such as biotite, feldspar, and quartz, are likely deposited as a result of concomitant fluid–rock interaction. High fluid temperatures (i.e., 400–500 °C) favor pentlandite formation due to an increase in Ni solubility. The pentlandite-pyrrhotite-biotite assemblage has a narrow stability field coinciding with a field of elevated Au solubility, which prevents coprecipitation of native gold with this mineral assemblage. In contrast, the pentlandite-arsenide mineral assemblage shows a larger stability field which overlaps with conditions allowing Au precipitation. The modeling results suggest that identification of the mineral assemblages in which pentlandite occurs is important in mineral exploration, one implication being that pentlandite-rich, hydrothermal veins will be expected to be Au-free. Conversely, pentlandite-poor or -absent veins, possibly containing Ni-arsenide minerals, may contain gold and could thus be indicative of enhanced prospectivity for gold.","PeriodicalId":218967,"journal":{"name":"The Canadian Journal of Mineralogy and Petrology","volume":"62-63 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124020204","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Silicate Glass / Crystal Inclusions (some with PGM / Cr-Spinel) in Placer Pt-Fe Alloy Nuggets, Northwest Ecuador: Genesis and Evolution of a Ural-Alaskan Type Zoned Intrusion","authors":"B. Barron, L. Barron, K. Goemann, L. Danyushevsky","doi":"10.3749/2200048","DOIUrl":"https://doi.org/10.3749/2200048","url":null,"abstract":"\u0000 Newly discovered placer Pt-Fe alloy nuggets from an unknown source intrusion, NW Ecuador, host abundant glass-only and micro-porphyritic silicate inclusions ± multiphase platinum group minerals. Glass-only (whole-rock) compositions form a fractionated comagmatic series of hydrous melts from ferrobasalt (one coexisting with Cr-spinel) to ferrobasalt and basaltic andesite to andesite; groundmass silicate glass is extremely fractionated dacite–rhyolite. Rare zoned plagioclase is bytownite centrally; our proposed primitive melt is picrobasalt. The samples exhibit a tholeiitic fractionation trend toward iron enrichment, then move sharply away toward calc-alkaline compositions with unusual mineralogy, analogous to experimental hydrous ferrobasalt. Trace elements confirm oceanic island arc basalt affinity with negative Nb, Ta anomalies and enriched large ion lithophile element content, similar to their host accreted Naranjal arc terrane. Potassium enrichment, superchondritic Nb/Ta, and Zr depletion suggest a deep-seated possible back-arc setting and ‘wet' melts. Cr-spinel inclusion chemistry indicates zoned Ural-Alaskan type affinity. We propose an ultramafic cumulate mush at depth with trapped inter-cumulous hydrous basaltic residual melts that ‘flush' chromitite layers/lenses ‘collecting' interstitial Pt-Fe alloy. Progressively fractionated ‘wet' residual melts also concentrate PGE-clusters and ligands, facilitating platinum group minerals crystallization during mush/melt intrusion within a fault-located conduit/pipe. Compressed by the intruding cumulate, the latest fractionating ‘wet' melts are sequentially expelled, forming typical cylindrical zoned layering.","PeriodicalId":218967,"journal":{"name":"The Canadian Journal of Mineralogy and Petrology","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126509574","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evanichite, Pb6Cr3+(Cr6+O4)2(SO4)(OH)7FCl, from Tiger, Arizona, USA, the First Mineral Containing Both Cr3+ and Cr6+","authors":"Hexiong Yang, R. Gibbs, Francis X. Sousa, R. Downs","doi":"10.3749/2200068","DOIUrl":"https://doi.org/10.3749/2200068","url":null,"abstract":"\u0000 A new mineral species, evanichite (IMA 2022-033), ideally Pb6Cr3+(Cr6+O4)2(SO4)(OH)7FCl, has been discovered from the Mammoth-Saint Anthony mine, Tiger, Arizona, USA. It occurs as a single group of subparallel short prismatic crystals on top of a quartz matrix. Individual crystals are up to 0.70 × 0.20 × 0.20 mm in size. Associated minerals include georgerobinsonite, bobmeyerite, pinalite, diaboleite, boleite, leadhillite, caledonite, cerussite, calcite, baryte, and fluorite. Evanichite is orange-brown to red-brown in transmitted light, transparent with a white streak and an adamantine luster. It is brittle and has a Mohs hardness of 2½−3 with perfect cleavage on {100}. No twinning was observed. The calculated density is 5.878 g/cm3. Evanichite is insoluble in water or hydrochloric acid. An electron probe microanalysis yielded an empirical formula [based on 21 (O+F+Cl) apfu] of Pb5.91(Cr3+0.81Fe3+0.11)Σ0.92(Cr6+O4)2(S1.07O4)(OH)7F0.99Cl1.05, which can be simplified to Pb6(Cr3+,Fe3+)(Cr6+O4)2(SO4)(OH)7FCl.\u0000 Evanichite is trigonal with space group P3 and unit-cell parameters a = 7.7651(14), c = 9.6199(17) Å, V = 502.3(2) Å3, and Z = 1. Its crystal structure consists of two unique Pb polyhedra [Pb1 coordinated by (5O + 3OH) and Pb2 by (5O + 2OH + F + Cl)], one M3+(OH)6 octahedron (M = Cr3+ + Fe3+), two Cr6+O4 tetrahedra (Cr1 and Cr2), and one SO4 tetrahedron. These polyhedra form four different layers parallel to (001). Layer 1 consists of edge- and corner-shared Pb1 polyhedra, layer 2 of isolated Cr1 and Cr2 tetrahedra, layer 3 of edge- and corner-shared Pb2 polyhedra, and layer 4 of isolated Cr3+(OH)6 octahedra and SO4 tetrahedra. These layers are stacked along [001] in the sequence layer 4 + layer 3 + layer 2 + layer 1 + layer 4. Both Pb1 and Pb2 cations are coordinated to anions with four short Pb–Φ (Φ = O, OH, F, or Cl) distances between 2.37 and 2.60 Å on one side and four (for Pb1) or five (for Pb2) long Pb–Φ distances ranging from 2.84 and 3.19 Å on the other side, indicating that both of them are lone-pair stereoactive. Evanichite is the first mineral that contains both Cr3+ and Cr6+, as well as the first chromate-sulfate compound with (CrO4)2− and (SO4)2− occupying distinct crystallographic sites.","PeriodicalId":218967,"journal":{"name":"The Canadian Journal of Mineralogy and Petrology","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130250668","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Zero Fault Pegmatite is Associated with Marble at Franklin, New Jersey, USA","authors":"J. Puffer","doi":"10.3749/2200030","DOIUrl":"https://doi.org/10.3749/2200030","url":null,"abstract":"\u0000 The Zero Fault Pegmatite is a large, unzoned pegmatite of graphic granite that is well exposed along quarry walls at Franklin, New Jersey. It is contained within the Franklin Marble and intersects the Zero Fault. New geochemical data has facilitated development of a three-step process responsible for its origin: (1) Anatectic partial fusion of a potassic metarhyolite (mapped as Microcline Gneiss) which occurred during peak-Ottawan (∼1045 Ma) granulite-facies metamorphism (∼770 °C and 600 MPa). Most of the resulting anatectic melt phase recrystallized in situ to form the leucosome of the Microcline Gneiss, but some persisted from late- to post-orogenesis and plots between the 720 and 730 °C isotherms of the 500 MPa phase diagram for the haplogranite, consistent with some relaxation and cooling from peak conditions. This residual and incompatible element enriched melt intruded along penetrating structures to form a local cluster of small, equally potassic granite plutons mapped as the Mt. Eve Granite. (2) Intrusion of the Mt. Eve Granite into marble layers, during which the anatectic melt underwent dense mineral fractionation, resulted in the formation of the Zero Fault Pegmatitic melt. (3) The melt encountered CO2 vapors, which reduced H2O activity, increased solidus temperatures, and resulted in significant undercooling. The latter led to rapid crystallization (at 720 to 740 °C), leading to development of a quenched, graphic texture. While the emplacement of graphic granite into marble is common among pegmatites, notably those in the Grenville Province, the proposed explanation provides insights into their general formation.","PeriodicalId":218967,"journal":{"name":"The Canadian Journal of Mineralogy and Petrology","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125073266","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mineralogy of K-Rich Rocks from the Jharia Basin in Jharkhand: Indications for Cretaceous Lamproite Magmatism in Eastern India","authors":"Parminder Kaur, S. C. Patel, R. Mitchell, S. Tappe, K. Pruseth, Jaspreet Saini, Amritpaul Singh, Gurmeet Kaur","doi":"10.3749/2200021","DOIUrl":"https://doi.org/10.3749/2200021","url":null,"abstract":"\u0000 Potassic dikes of early Cretaceous age (ca. 115 Ma) are emplaced in the Gondwana sedimentary basins of the Damodar valley in eastern India. Two potassic dikes in the Jharia basin (Ena and Moonidih) are characterized by the presence of olivine macrocrysts and phenocrysts, together with microphenocrysts of olivine, phlogopite–biotite, ilmenite, and apatite. These are set in a groundmass of phlogopite, apatite, ilmenite, spinel, and K-feldspar. Microphenocrystal and groundmass Al-Na-poor diopside and Al-poor Ti-rich amphibole are present in the Ena dike, whereas rutile, pyrite, galena, Zr-Ti-rich garnet, and quartz are minor phases occurring in the Moonidih dike. Two populations of relatively fresh olivine (I and II) are found in the Ena dike, in contrast to the Moonidih dike, where olivine macrocrysts and microphenocrysts are completely replaced by secondary magnesite, serpentine, and talc. The occurrence of fresh olivine in the Ena dike is reported for the first time in the Jharia basin. High forsterite (Fo) and Ni together with low Ca and Mn contents of the olivine-I macrocrysts suggest a mantle-derived xenocrystic origin. In contrast, the olivine-II population has high Ca and Mn, but relatively low Fo and Ni, suggesting a magmatic origin. Rimward decreasing Al and increasing Fe contents in zoned phlogopite crystals, plus the presence of groundmass spinel with compositions along the titanomagnetite trend (T2), indicate the lamproitic affinity of the K-rich dike rocks. Using a mineralogical-genetic classification scheme, the Ena and Moonidih dikes are classified as olivine-phlogopite-diopside-apatite-amphibole-feldspar lamproite and olivine-phlogopite-apatite-feldspar lamproite, respectively. We use the compositional variations of phlogopite, amphibole, apatite, and spinel to understand better the magmatic evolution and crystallization history of these potassic dikes. The Cretaceous lamproite magmatic event in eastern India was sourced from ancient metasomatized lithospheric mantle, with low-degree partial melting either triggered in the periphery of the impinging Kerguelen mantle plume head or induced by distant subduction.","PeriodicalId":218967,"journal":{"name":"The Canadian Journal of Mineralogy and Petrology","volume":"130 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122644225","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mineralogy of Pt-Pd sulfides: The Redefinition of Braggite and Vysotskite (with Comments on the Extent of Solid Solution in the PtS–PdS Binary)","authors":"L. Cabri, A. McDonald","doi":"10.3749/2200058","DOIUrl":"https://doi.org/10.3749/2200058","url":null,"abstract":"\u0000 A re-evaluation of data relating to the crystal structures, phase equilibria, and ideal chemical formulae of the key minerals belonging to the PtS–PdS binary, namely vysotskite, braggite, and cooperite, has led to redefinitions of the ideal chemical formulae for vysotskite and braggite. Results show that vysotskite and braggite are isostructural and crystallize in the space group P42/m. Their crystal structures contain three Me sites and a single S site, giving rise to the general crystal-chemical formula Me(1)2Me(2)2Me(3)4S8. Ordering of Pt and Pd leads to the revised ideal formula of Pd2Pd2Pd4S8 (Z = 1) for vysotskite, which can be simplified to PdS (Z = 8), and a revised ideal formula of Pd2Pt2Pt4S8 (Z = 1) for braggite, which can be simplified to PdPt3S4 (Z = 2). Cooperite, ideally PtS (Z = 8), crystallizes in a related, but different, space group, P42/mmc. Its crystal structure contains a single Me and S site. Both Pt and Pd are disordered over the Me site but with Pt > Pd . Oversimplification of the ideal chemical formulae for all these minerals and failure to consider crystal-structure implications has led to confusion in the literature.\u0000 Consideration of experimental data combined with that for minerals from world-wide occurrences suggests complete solid solution between vysotskite and braggite, but of a more limited degree between cooperite and braggite, consistent with what would be expected when their respective crystal structures are considered. The maximum Pt possible in braggite should correspond to (Pd0.51Pt0.49)Σ1Pt3S4 (or Pd0.51Pt3.49S4); Pt:Pd = 0.87, which requires Pd 6.29, Pt 78.86, S 14.85, total 100.00 wt.%) and the maximum Pd content, to Pd(Pt0.505Pd0.495)Σ1(Pt1.505Pd0.495)Σ2S4 (or Pd1.99Pt2.01S4); Pt:Pd = 0.50, which requires Pd 28.93, Pt 53.56, S 17.52, total 100.00 wt.%). In light of the complete solid solution between vysotskite and braggite, the 50% rule should be applied to compositions between them. Thus, within the PtS–PdS binary, it is recommended that (1) vysotskite be used for those minerals having compositions ranging from 100 to 56.5 mol.% PdS; (2) braggite, for those having compositions that range from 56.5 to 13 mol.% PdS; and (3) cooperite, for those having <13 mol.%.","PeriodicalId":218967,"journal":{"name":"The Canadian Journal of Mineralogy and Petrology","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129904103","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Betzite, Na6Ca2(Al6Si6O24)Cl4, a New Cancrinite-Group Mineral from the Eifel Paleovolcanic Region, Germany","authors":"N. Chukanov, N. Zubkova, O. Kazheva, D. Varlamov, I. Pekov, D. Belakovskiy, B. Ternes, W. Schüller, S. Britvin, D. Pushcharovsky","doi":"10.3749/2200039","DOIUrl":"https://doi.org/10.3749/2200039","url":null,"abstract":"\u0000 Betzite, ideally Na6Ca2(Al6Si6O24)Cl4, a new cancrinite-group mineral, was discovered in a metasomatically altered (pyrometamorphosed) calcic xenolith, hosted by alkaline basalt at the Bellerberg paleovolcano in the Eastern Eifel region, Rhineland-Palatinate, Germany. The associated minerals are anorthite, phlogopite, diopside, grossular, fluorite, calcite, a tobermorite-like mineral, and vanadoallanite-(Ce). Betzite occurs as colorless hexagonal prismatic crystals up to 2 mm long and up to 0.5 mm thick. The new mineral is brittle, with a Mohs' hardness of 5½. Distinct cleavage on {100} and parting on {0001} are observed. The Dmeas = 2.38(2) g/cm3 and Dcalc = 2.363 g/cm3. Betzite is optically uniaxial (+) with ω = 1.528(2) and ε = 1.545(3). The IR spectrum is given. The chemical composition of betzite is (wt.%; electron microprobe, H2O determined by the modified Penfield method): Na2O 11.88, K2O 4.82, CaO 10.74, MgO 0.21, Al2O3 27.32, Fe2O3 0.68, SiO2 32.84, SO3 1.89, Cl 10.48, H2O 1.10, −O≡Cl −2.37, total 99.59. The empirical formula is Na4.22K1.13Ca2.11Mg0.06(Si6.01Al5.90Fe3+0.09O24)Cl3.25(SO4)0.26(H1.34O0.64). The crystal structure was determined using single-crystal X-ray diffraction data. It is hexagonal, space group P63, a = 12.8166(9) Å, c = 5.3562(3) Å, V = 761.95(12) Å3 (at a temperature of 100 K) and Z = 3. Betzite is a dimorph of quadridavyne, with a disordered distribution of extra-framework components occupying channels. The strongest lines of the powder X-ray diffraction pattern [d, Å (I, %) (hkl)] are: 11.14 (31) (100), 4.833 (93) (101), 3.715 (95) (300), 3.313 (100) (211), 2.787 (37) (400), 2.681 (56) (002, 131), 2.474 (35) (112, 401), 2.146 (24) (330). The mineral is named in honor of the German amateur mineralogist Volker Betz (b. 1947).","PeriodicalId":218967,"journal":{"name":"The Canadian Journal of Mineralogy and Petrology","volume":"115 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128928517","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"New Minerals from the Redmond Mine, North Carolina, USA: I. Redmondite, Hydroredmondite, and Sulfatoredmondite, Three Minerals Containing the Novel [Pb8O2Zn(OH)6]8+ Structural Unit","authors":"A. R. Kampf, Jason B. Smith, John M. Hughes, Chiu‐Shun Ma, Christopher R. Emproto","doi":"10.3749/2200059","DOIUrl":"https://doi.org/10.3749/2200059","url":null,"abstract":"\u0000 The new minerals redmondite (IMA2021–072), [Pb8O2Zn(OH)6](S2O3)4, hydroredmondite (IMA2021–073), [Pb8O2Zn(OH)6](S2O3)4·2H2O, and sulfatoredmondite (IMA2021–089), [Pb8O2Zn(OH)6](SO4)4·6H2O, were found in the Redmond mine, Haywood County, North Carolina, USA, where they occur together in a highly unusual secondary assemblage that comprises a variety of rare Pb-Zn-Cu sulfates, thiosulfates, and carbonates. The properties of redmondite are as follows: colorless to shades of brown, transparent equant rhombs to about 1 mm; white streak; adamantine luster; brittle; Mohs hardness 2; conchoidal fracture; no cleavage; 5.757 g/cm3 calculated density; biaxial with α = 1.96–1.97, β = 1.97–1.98, γ = 1.97–1.98; extreme dispersion. The properties of hydroredmondite are as follows: colorless, transparent prisms, blades, and tablets up to about 1 mm; white streak; adamantine luster; brittle; Mohs hardness 2; curved and stepped fracture; good cleavages on {101} and ; 5.124 g/cm3 calculated density; biaxial (+) with α = 1.830(5), β = 1.880(calc), γ = 1.950(calc), 2Vmeas = 83(1)°. The properties of sulfatoredmondite are as follows: colorless, transparent wedge-shaped crystals to about 2 mm; white streak; adamantine luster; brittle; Mohs hardness 2; curved, irregular fracture; no cleavage; 5.173 g/cm3 calculated density; biaxial (+), α = 1.780(5), β = 1.850(calc), γ = 1.860(calc), 2Vmeas = 40(3)°; moderate r > v dispersion. Electron probe microanalyses provided the empirical formulae: Pb8.16Zn1.00S6+3.97S2−3.97O20H5.79, Pb8.00Zn1.00S6+4.00S2−4.00O22H9.98, and Pb8.00Zn0.99S6+4.00S2−0.89O29.11H17.98 for redmondite, hydroredmondite, and sulfatoredmondite, respectively. Redmondite is monoclinic, P21/c, a = 9.1672(4), b = 10.6576(4), c = 14.0620(10) Å, β = 101.173(7)°, V = 1347.83(12) Å3, and Z = 2. Hydroredmondite is monoclinic, P21/n, a = 12.5991(9), b = 9.2819(4), c = 12.9774(9) Å, β = 90.443(6)°, V = 1517.57(16) Å3, and Z = 2. Sulfatoredmondite is monoclinic, C2/m, a = 17.294(2), b = 7.3668(9), c = 12.7271(18) Å, β = 110.622(9)°, V = 1517.5(4) Å3, and Z = 2. The crystal structures of redmondite (R1 = 0.0346 for 2061 I > 2σI), hydroredmondite (R1 = 0.0346 for 3022 I > 2σI), and sulfatoredmondite (R1 = 0.0344 for 1661 I > 2σI) are all based on the same [Pb8O2Zn(OH)6]8+ structural unit.","PeriodicalId":218967,"journal":{"name":"The Canadian Journal of Mineralogy and Petrology","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122254434","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}