Mineralogical Magazine最新文献

{"title":"Fluorbritholite-(Nd), Ca2Nd3(SiO4)3F, a new and a key mineral for neodymium sequestration in REE skarns","authors":"D. Holtstam, Patrick Casey, L. Bindi, H. Förster, A. Karlsson, Oona Appelt","doi":"10.1180/mgm.2023.45","DOIUrl":"https://doi.org/10.1180/mgm.2023.45","url":null,"abstract":"Fluorbritholite-(Nd), ideally Ca 2 Nd 3 (SiO 4 ) 3 F, is an approved mineral (IMA 2023-001) and constitutes a new member of the britholite group of the apatite supergroup. It occurs in skarn from the Malmkärra iron mine, Norberg, Västmanland (one of the Bastnäs-type deposits in Sweden), associated with calcite, dolomite, magnetite, lizardite, talc, fluorite, baryte, scheelite, gadolinite-(Nd) and other REE minerals. Fluorbritholite-(Nd) forms anhedral and small grains, rarely up to 250 µm across. They are brownish pink, transparent with a vitreous to greasy luster. The mineral is brittle, with an uneven or subconchoidal fracture, and lacks a cleavage. In thin section, the mineral is nonpleochroic, uniaxial (-). D calc = 4.92(1) g·cm − 3 and","PeriodicalId":18618,"journal":{"name":"Mineralogical Magazine","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2023-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48651935","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Bakakinite, Ca2V2O7, a new mineral from fumarolic exhalations of the Tolbachik volcano, Kamchatka, Russia","authors":"I. Pekov, A. Agakhanov, N. Koshlyakova, N. Zubkova, V. Yapaskurt, S. Britvin, M. Vigasina, A. Turchkova, M. Nazarova","doi":"10.1180/mgm.2023.42","DOIUrl":"https://doi.org/10.1180/mgm.2023.42","url":null,"abstract":"Abstract The new mineral bakakinite, ideally Ca2V2O7, was found in the high-temperature (not lower than 500°C) exhalations of the Arsenatnaya fumarole at the Second scoria cone of the Northern Breakthrough of the Great Tolbachik Fissure Eruption, Tolbachik volcano, Kamchatka, Russia. It is associated with anhydrite, svabite, pliniusite, schäferite, berzeliite, diopside, hematite, powellite, baryte, fluorapatite, calciojohillerite, ludwigite, magnesioferrite, anorthite, titanite and esseneite. Bakakinite forms flattened crystals up to 30 × 5 μm, typically distorted. The mineral is transparent, colourless or pale yellow, with strong vitreous lustre. Electron microprobe analysis gave (wt.%): CaO 37.04, SrO 0.26, SiO2 0.16, P2O5 1.48, V2O5 49.47, As2O5 10.85, SO3 0.35, total 99.61. The empirical formula calculated on the basis of 7 O apfu is (Ca1.99Sr0.01)Σ2.00(V1.64As0.28P0.06Si0.01S0.01)Σ2.00O7. The Dcalc is 3.463 g cm–3. Bakakinite is triclinic, P$bar{1}$, unit-cell parameters are: a = 6.64(2), b = 6.92(2), c = 7.01(2) Å, α = 86.59(7), β = 63.77(7), γ = 83.47(6)°, V = 287.0(5) Å3 and Z = 2. The strongest reflections of the powder X-ray diffraction pattern [d,Å(I)(hkl)] are: 4.647(27)(111, 0$bar{1}$1), 3.138(76)(002), 3.103(100)(120, 121), 3.027(20)(021), 2.960(81)(200), 2.158(19)(031, 302), 1.791(16)(320), 1.682(16)(114) and 1.584(17)(1$bar{3}$3, 403). Bakakinite is a natural analogue of synthetic Ca2V2O7. The mineral is named in honour of the outstanding Russian crystallographer and crystal chemist Vladimir Vasilievich Bakakin (born 1933).","PeriodicalId":18618,"journal":{"name":"Mineralogical Magazine","volume":"1 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2023-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41631530","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reply to Bosi et al. (2023)","authors":"F. Hawthorne","doi":"10.1180/mgm.2023.35","DOIUrl":"https://doi.org/10.1180/mgm.2023.35","url":null,"abstract":"to XXII meeting of the IMA, Melbourne, Australia, 2018, 354. Bosi F., Hatert F, Hålenius U., Pasero M., Miyawaki R. and Mills S.J. (2019a) On the application of the IMA−CNMNC dominant-valency rule to complex mineral compositions. Mineralogical Magazine, 83, 627–632. Bosi F., Biagioni C. and Oberti R. (2019b) On the chemical identification and classification of minerals. Minerals, 9, 591–603. Bosi F., Hatert F., Pasero M., Mills S.J., Miyawaki R. and Halenius U. (2023) A brief comment on Hawthorne (2023): “On the definition of distinct mineral species: A critique of current IMA-CNMNC procedures”.Mineralogical Magazine, 87, 505–507, doi:10.1180/mgm.2023.33 Gagné O. and Hawthorne F.C. (2016) Chemographic exploration of the milarite-type structure. The Canadian Mineralogist, 54, 1229–1247. Hatert F. and Burke E.A.J. (2008) The IMA–CNMNC dominant-constituent rule revisited and extended. The Canadian Mineralogist, 46, 717–728. Hawthorne F.C. (2002) The use of end-member charge-arrangements in defining new mineral species and heterovalent substitutions in complex minerals. The Canadian Mineralogist, 40, 699–710. Hawthorne F.C. (2021) Proof that a dominant endmember formula can always be written for a mineral or a crystal structure. The Canadian Mineralogist, 59, 159–167. Hawthorne F.C. (2023) On the definition of distinct mineral species: A critique of current IMA-CNMNC procedures. Mineralogical Magazine, 87, 494– 504, doi:10.1180/mgm.2023.8 Hawthorne F.C., Sokolova E., Agakhanov A.A., Pautov L.A., Karpenko V.Yu. and Grew E.S. (2018) Chemographic exploration of the hyalotekite structure-type. Mineralogical Magazine, 82, 929–937. Hawthorne F.C., Mills S.J., Hatert F. and Rumsey M.S. (2021) Ontology, archetypes and the definition of “mineral species”. Mineralogical Magazine, 85, 125–131; erratum, 85, 830. Nickel E.H. (1992) Solid solutions in mineral nomenclature. The Canadian Mineralogist, 30, 231–234. Nickel E.H. and Grice J.D. (1998) The IMA commission on new minerals and mineral names: procedures and guidelines on mineral nomenclature. The Canadian Mineralogist, 36, 913–926. 510 Frank C. Hawthorne","PeriodicalId":18618,"journal":{"name":"Mineralogical Magazine","volume":"87 1","pages":"508 - 510"},"PeriodicalIF":2.7,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42131174","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"MGM volume 87 issue 3 Cover and Front matter","authors":"","doi":"10.1180/mgm.2023.47","DOIUrl":"https://doi.org/10.1180/mgm.2023.47","url":null,"abstract":"","PeriodicalId":18618,"journal":{"name":"Mineralogical Magazine","volume":" ","pages":"f1 - f1"},"PeriodicalIF":2.7,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44309166","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Vrančiceite, Cu10Hg3S8, a new Cu-Hg sulfide mineral from Vrančice, Czech Republic","authors":"J. Sejkora, C. Biagioni, P. Škácha, D. Mauro","doi":"10.1180/mgm.2023.40","DOIUrl":"https://doi.org/10.1180/mgm.2023.40","url":null,"abstract":"Abstract Vrančiceite is a new mineral species discovered in a sample collected from the old mine dumps of the abandoned Vrančice deposit near Příbram, central Bohemia, Czech Republic. Vrančiceite occurs as rare anhedral grains, up to 100 μm in size, in a calcite gangue, associated with cinnabar, djurleite, galena and hedyphane. Vrančiceite is black, with metallic lustre. Mohs hardness is ca. 2–3, calculated density is 6.652 g.cm–3. In reflected light, vrančiceite is light grey with a yellowish shade; bireflectance, pleochroism and anisotropy are all weak. Internal reflections were not observed. Reflectance values for the four Commission on Ore Mineralogy wavelengths of vrančiceite in air [Rmax, Rmin (%) (λ in nm)] are: 33.6, 31.2 (470); 33.9, 30.6 (546); 31.1, 30.0 (589); and 32.1, 29.1 (650). The empirical formula, based on electron-microprobe analyses, is Cu10.11(4)Ag0.01(1)Hg2.87(4)Sb0.01(1)Bi0.01(1)S7.99(8). The ideal formula is Cu10Hg3S8 (Z = 2), which requires (in wt.%) Cu 42.54, Hg 40.29 and S 17.17, total 100.00. Vrančiceite is triclinic, P$bar{1}$, with unit-cell parameters a = 7.9681(2), b = 9.7452(3), c = 10.0710(3) Å, α = 77.759(1), β = 76.990(1), γ = 79.422(1)°, V = 737.01(4) Å3 and Z = 2. The strongest reflections of the calculated powder X-ray diffraction pattern [d, Å (I) hkl] are: 3.354 (76) $bar{2}$01, 3.111 (68) 222, 2.833 (100) 213, 2.733 (93) 231, 2.705 (76) 2$bar{2}$1 and 2.647 (71) $bar{2}bar{1}$2. According to the single-crystal X-ray diffraction data (R1 = 0.0262), the crystal structure of vrančiceite can be described as comprising Cu–S layers, connected through CuS3 polyhedra, giving rise to a three-dimensional framework with channels running along the a axis and hosting linearly coordinated Hg atoms. Structural relations with gortdrumite are discussed. Vrančiceite is named after its type locality, the Vrančice deposit near Příbram. The mineral and its name have been approved by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association (IMA2022–114).","PeriodicalId":18618,"journal":{"name":"Mineralogical Magazine","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2023-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43484079","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tennantite-(Ni), Cu6(Cu4Ni2)As4S13, from Luobusa ophiolite, Tibet, China: a new Ni member of the tetrahedrite group","authors":"Yanjuan Wang, Rujun Chen, X. Gu, Z. Hou, F. Nestola, Zhusen Yang, Guang Fan, G. Dong, Lijuan Ye, Kai Qu","doi":"10.1180/mgm.2023.41","DOIUrl":"https://doi.org/10.1180/mgm.2023.41","url":null,"abstract":"Abstract The new mineral tennantite-(Ni), Cu6(Cu4Ni2)As4S13, has been discovered from the Luobusa Chromitite, Tibet, southwestern China. Tennantite-(Ni) occurs as anhedral grains ranging from 2 to 20 μm in size. In reflected light microscopy, tennantite-(Ni) is isotropic and appears yellow-greenish grey. Reflectance data for Commission on Ore Mineralogy wavelengths in air for tennantite-(Ni) are: 31.0 (470 nm), 29.6 (546 nm), 29.6 (589 nm) and 29.3 (650 nm). Electron microprobe analysis for holotype material gave the empirical formula (on basis of total cations = 16 apfu): M(2)Cu6 M(1)[Cu4.00(Ni0.97Cu0.53Fe0.50)Σ2.00]Σ6.00X(3)(As2.94Sb1.06)Σ4S12.77. Tennantite-(Ni) is cubic, with space group I$bar{ 4}$3m (#217), a =10.2957(9) Å, V = 1091.4(3) Å3 and Z = 2. By using single-crystal X-ray diffraction, the crystal structure has been determined and refined to a final R1 = 0.0423 on the basis of 163 independent reflections [Fo > 4σ (Fo)]. The calculated seven strongest powder X-ray diffraction lines [d in Å (I) (hkl)] are: 2.972 (100) (222), 1.820 (83) (440), 2.574 (28) (400), 1.552 (18) (622), 3.640 (10) (220), 1.880 (10) (521) and 1.287 (7) (800). Tennantite-(Ni) is isostructural with other tetrahedrite-group minerals, and nickel is hosted at the tetrahedrally coordinated M(1) site, along with Cu and minor Fe. The mineral and its name have been approved by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association (IMA2021-018).","PeriodicalId":18618,"journal":{"name":"Mineralogical Magazine","volume":"87 1","pages":"591 - 598"},"PeriodicalIF":2.7,"publicationDate":"2023-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44895579","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mineral chemistry and genesis of monazite-(Sm) and monazite-(Nd) from the Blue Beryl Dyke of the Julianna pegmatite system at Piława Górna, Lower Silesia, Poland","authors":"Diana Twardak, A. Pieczka, J. Kotowski, K. Nejbert","doi":"10.1180/mgm.2023.38","DOIUrl":"https://doi.org/10.1180/mgm.2023.38","url":null,"abstract":"Abstract Monazites are one of the most interesting groups of accessory mineral components of crystalline rocks due to the information on geochemical evolution of the crystallisation environment coded in their chemical compositions, in addition to comprising one of the most valuable objects for geochronology studies. This paper presents monazite-(Sm) and monazite-(Nd) from the Blue Beryl Dyke of the Julianna system of rare-element pegmatites at Piława Górna, Lower Silesia, Poland. These monazites are unique due to their unusually high Sm and Nd contents, reaching 33.22 wt.% Sm2O3 and 34.12 wt.% Nd2O3, respectively. We consider the most significant factors of the enrichment in Sm and Nd to be the occurrence of highly fractionated pegmatite-forming melts during the final stages of solidification and associated hydrothermal fluids that were strongly enriched in rare earth element REE–Cl and REE–F complexes. Local disequilibria allowed for the rapid growth of accessory phases under supercooling conditions associated with the scavenging of selected elements, leading to their local depletion, which was not balanced by diffusion processes. As a consequence, the depletion of light rare earth elements (LREE) led to the incorporation of available middle rare earth elements (MREE, Sm–Dy) in the case of Sm and Nd, which could occupy an acceptable structural position in minerals of the monazite group.","PeriodicalId":18618,"journal":{"name":"Mineralogical Magazine","volume":"87 1","pages":"575 - 581"},"PeriodicalIF":2.7,"publicationDate":"2023-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47387720","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reply to the discussion of Galuskin and Galuskina (2023) “Evidence of the anthropogenic origin of the ‘Carmel sapphire’ with enigmatic super-reduced minerals” by Griffin et al. (2023)","authors":"E. Galuskin, I. Galuskina","doi":"10.1180/mgm.2023.39","DOIUrl":"https://doi.org/10.1180/mgm.2023.39","url":null,"abstract":"At the beginning of their discussion, Griffin et al. (2023) thank us for our detailed investigation of corundum aggregates from Carmel Mt, Northern Israel, which, in their opinion, is “a useful supplement” to their previous publications. We would also like to thank Griffin et al., whose denial of the existence of ‘white breccia’ (corundum angular fragments of different size in white cement) simplifies our defence of our position. In our paper (Galuskin and Galuskina, 2023) we provide mineralogical evidence that ‘Carmel sapphire’ has an anthropogenic genesis based on the study of ‘white breccia’, which consists of the waste of electrocorundum (fused alumina, refractory abrasive material) production. It seems if there is no ‘white breccia’, then our evidence of the anthropogenic genesis of Carmel sapphire does not matter. However Griffin et al. (2019a) were the first to use the term ‘white breccia’. Both in their scientific publications and in the reporting documents of the Shefa Yamim exploration company, there are images of ‘white breccia’ with Carmel sapphire or corundum grains with a white coating (Xiong et al., 2017; Griffin et al., 2021a; Galuskin and Galuskina, 2023, figure S9, supplementary materials). At this point, we can close the discussion with two brief conclusions: (1) Griffin et al. (2023) debate plenty of secondary issues that divert attention from the main object, ‘white breccia’, which is key to solving the problem of Carmel sapphire genesis; (2) ‘white breccia’ (in the form of individual samples) exists and consists of the waste of electrocorundum production. However we decided that readers can draw their own conclusions after reading our paper (Galuskin and Galuskina, 2023) and the discussion connected with it; we answer most of the remarks of Griffin et al. (2023) below.","PeriodicalId":18618,"journal":{"name":"Mineralogical Magazine","volume":"87 1","pages":"635 - 638"},"PeriodicalIF":2.7,"publicationDate":"2023-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42363816","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Monazite-(Gd), a new Gd-dominant mineral of the monazite group from the Zimná Voda REE–U–Au quartz vein, Prakovce, Western Carpathians, Slovakia","authors":"M. Ondrejka, P. Uher, Š. Ferenc, J. Majzlan, K. Pollok, T. Mikuš, S. Milovská, Alexandra Molnárová, R. Škoda, Richard Kopáčik, S. Kurylo, P. Bačík","doi":"10.1180/mgm.2023.37","DOIUrl":"https://doi.org/10.1180/mgm.2023.37","url":null,"abstract":"Abstract Monazite-(Gd), ideally GdPO4, is a new mineral of the monazite group. It was discovered near Prakovce-Zimná Voda, ~23 km WNW of Košice, Western Carpathians, Slovakia. It forms anhedral domains (≤100 μm, mostly 10–50 μm in size), in close association with monazite-(Sm), Gd-bearing xenotime-(Y), Gd-bearing hingganite-(Y), fluorapatite and uraninite. All these minerals are hosted in a REE–U–Au quartz–muscovite vein, hosted in phyllites in an exocontact to granites. The density calculated using the average empirical formula and unit-cell parameters is 5.55 g/cm3. The average chemical composition measured by means of electron microprobe is as follows (wt.%): P2O5 29.68, As2O5 0.15, SiO2 0.07, ThO2 0.01, UO2 0.04, Y2O3 1.30, La2O3 3.19, Ce2O3 6.93, Pr2O3 1.12, Nd2O3 10.56, Sm2O3 17.36, Eu2O3 1.49, Gd2O3 22.84, Tb2O3 1.57, Dy2O3 2.27, CaO 0.21, total 99.67. The corresponding empirical formula calculated on the basis of 4 oxygen atoms is: (Gd0.30Sm0.24Nd0.15Ce0.10La0.05Dy0.03Y0.03Tb0.02Eu0.02Pr0.02Ca0.01)0.98P1.01O4. The ideal formula is GdPO4. The monazite-type structure has been confirmed by micro-Raman spectroscopy and selected-area electron diffraction. Monazite-(Gd) is monoclinic, space group P21/n, a = 6.703(1) Å, b = 6.914(1) Å, c = 6.383(1) Å, β = 103.8(1)°, V = 287.3(1) Å3 and Z = 4. The middle REE enrichment of monazite-(Gd) is shared with the associated Gd-bearing xenotime-(Y) to ‘xenotime-(Gd)’ and Gd-bearing hingganite-(Y). This exotic REE signature and precipitation of Gd-bearing mineral assemblage is a product of selective complexing and enrichment in middle REE in low-temperature hydrothermal fluids by alteration of primary uraninite, brannerite and fluorapatite on a micro-scale. The new mineral is named as an analogue of monazite-(La), monazite-(Ce), monazite-(Nd) and monazite-(Sm) but with Gd dominant among the REE.","PeriodicalId":18618,"journal":{"name":"Mineralogical Magazine","volume":"87 1","pages":"568 - 574"},"PeriodicalIF":2.7,"publicationDate":"2023-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49187803","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dongchuanite, a new phosphate mineral with a new structure, from Dongchuan copper mine, Yunnan Province, China","authors":"Guowu Li, Ningyue Sun, Hongtao Shen, Yuan Xue, Jinhua Hao, Jeffrey de Fourestier","doi":"10.1180/mgm.2023.16","DOIUrl":"https://doi.org/10.1180/mgm.2023.16","url":null,"abstract":"Abstract Dongchuanite, ideally Pb4VIZnIVZn2(PO4)2(PO4)2(OH)2, is a new phosphate mineral with a new type of structure. It was found at the Dongchuan copper mine, Yunnan Province, People's Republic of China. Dongchuanite generally occurs as spherical aggregates with microscopic lamellar crystals, characterised by a turquoise–greenish blue colour. It is transparent, with a colourless streak and has a vitreous lustre without fluorescence. It is brittle with a Mohs hardness of 2–2½, and has good parallel cleavage to {011}, with insignificant parting and even fracture. According to the empirical formula and cell volume, it has a calculated density of 6.06 g/cm3. It easily dissolves in acid without gas being emitted. The mineral is biaxial (–), calculated n = 1.90 and maximum birefringence: δ = 0.010 and 2V=70°. Dispersion of the optical axes r < v is very weak. The mineral is pale blue to light blue and very weakly pleochroic in transmitted light. Dongchuanite crystallises in the triclinic space group P$bar{1}$, with unit-cell parameters a = 4.7620(10) Å, b = 8.5070(20) Å, c = 10.3641(19) Å, α = 97.110(17)°, β = 101.465(17)°, γ = 92.273(18)°, V = 407.44(15) Å3 and Z = 1. The eight strongest reflections in the powder X-ray diffraction pattern [dobs, Å (I/I0) (hkl)] are: 3.442 (100) ($bar{1}$12), 3.035 (50) (120), 4.652 (45) (100), 2.923 (40) ($bar{1}bar{1}$3), 2.384 (35) ($bar{2}$01), 3.130 (30) ($bar{1}$21), 2.811 (30) (030) and 2.316 (18) (032). The crystal structure (solved and refined from single-crystal X-ray diffraction data, R1 = 0.07) is a new layered structure consisting of corner-sharing tetrahedrons and octahedrons, where [PO4] tetrahedra and [ZnO4] tetrahedra share corners to form a double chain, and the another [PO4] tetrahedra is connected by corner-sharing with a [ZnO4(OH)2] octahedra to form a tetrahedral–octahedral chain, extending along the a-axis direction. The two types of chains are connected by corner-sharing between [ZnO4] and [PO4] tetrahedra forming a wrinkled layer parallel to (011). The Pb atoms occupy two independent sites between the wrinkled layers, both of which have typical lopsided coordination of Pb2+ with stereoactive 6s2 lone-pair electrons.","PeriodicalId":18618,"journal":{"name":"Mineralogical Magazine","volume":"87 1","pages":"611 - 618"},"PeriodicalIF":2.7,"publicationDate":"2023-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47754460","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}