Mineralogical Magazine最新文献

{"title":"On the definition of distinct mineral species: A critique of current IMA–CNMNC procedures","authors":"F. Hawthorne","doi":"10.1180/mgm.2023.8","DOIUrl":"https://doi.org/10.1180/mgm.2023.8","url":null,"abstract":"Abstract The criteria for the definition of a new mineral species currently used by the Commission on New Minerals Nomenclature and Classification (CNMNC) of the International Mineralogical Association are critically examined. In particular, the rule of the dominant constituent can violate the laws of conservation of electric charge. A series of additional rules: (1) valency-imposed double site-occupancy; (2) the dominant-valency rule; and (3) the site-total-charge approach, have been developed in an attempt to correct this error. However, none of these rules can overcome the fundamental flaw introduced by the rule of the dominant constituent, and the chemical formulae resulting from application of these rules can violate the requirements of an end-member, particularly that of electroneutrality. As a result, the IMA–CNMNC rules cannot derive end-member formulae for some groups of minerals, giving rise to many ad hoc decisions in defining distinct mineral species.","PeriodicalId":18618,"journal":{"name":"Mineralogical Magazine","volume":"87 1","pages":"494 - 504"},"PeriodicalIF":2.7,"publicationDate":"2023-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43065037","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":"On the matildite–bohdanowiczite solid-solution series","authors":"P. Alexandre, Moses Aisida","doi":"10.1180/mgm.2023.4","DOIUrl":"https://doi.org/10.1180/mgm.2023.4","url":null,"abstract":"Abstract A high-grade ore sample from the Cu–Zn–Au Photo Lake volcanogenic massive sulfide deposit (Flin Flon–Snow Lake greenstone belt, Manitoba, Canada) contains a Bi–Ag sulfo-selenide with a composition situated approximately in the middle of the S–Se substitution range (Se ≈ 0.86 apfu and S ≈ 1.05 apfu). These new data, combined with a literature compilation of all publicly available matildite and bohdanowiczite compositional data, reveal a nearly complete range of S–Se substitution between these two minerals, with only the section between BiAgSe0.78S1.18 and BiAgSe0.25S1.75 – about a quarter of the complete S–Se range – not yet documented. These observations suggest that a complete solid-solution series between matildite and bohdanowiczite, as previously suspected, might exist and in a manner similar to the galena–clausthalite complete solid-solution series.","PeriodicalId":18618,"journal":{"name":"Mineralogical Magazine","volume":"87 1","pages":"292 - 299"},"PeriodicalIF":2.7,"publicationDate":"2023-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44020242","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":"Bernardevansite, Al2(Se4+O3)3⋅6H2O, dimorphous with alfredopetrovite and the Al-analogue of mandarinoite, from the El Dragón mine, Potosí, Bolivia","authors":"Hexiong Yang, X. Gu, R. Jenkins, R. Gibbs, R. Downs","doi":"10.1180/mgm.2023.7","DOIUrl":"https://doi.org/10.1180/mgm.2023.7","url":null,"abstract":"Abstract A new mineral species, bernardevansite (IMA2022-057), ideally Al2(Se4+O3)3⋅6H2O, has been discovered from the El Dragón mine, Potosí Department, Bolivia. It occurs as aggregates or spheres of radiating bladed crystals on a matrix consisting of Co-bearing krut'aite–penroseite. Associated minerals are Co-bearing krut'aite–penroseite, chalcomenite and ‘clinochalcomenite’. Bernardevansite is colourless in transmitted light, transparent with white streak and vitreous lustre. It is brittle and has a Mohs hardness of 2½–3. Cleavage is not observed. The measured and calculated densities are 2.93(5) and 2.997 g/cm3, respectively. Optically, bernardevansite is biaxial (+), with α = 1.642(5), β = 1.686(5) and γ = 1.74(1) (white light). An electron microprobe analysis yielded an empirical formula (based on 15 O apfu) (Al1.26Fe3+0.82)Σ2.08(Se0.98O3)3⋅6H2O, which can be simplified to (Al,Fe3+)2(SeO3)3⋅6H2O. Bernardevansite is the Al-analogue of mandarinoite, Fe3+2(SeO3)3⋅6H2O or dimorphous with P$bar{6}$2c alfredopetrovite. It is monoclinic, with space group P21/c and unit-cell parameters a = 16.5016(5), b = 7.7703(2), c = 9.8524(3) Å, β = 98.258(3)°, V = 1250.21(6) Å3 and Z = 4. The crystal structure of bernardevansite consists of a corner-sharing framework of M3+O6 (M = Al and Fe) octahedra and Se4+O3 trigonal pyramids, leaving large voids occupied by the H2O groups. There are two unique M3+ positions: M1 is octahedrally coordinated by (4O + 2H2O) and M2 by (5O + H2O). The structure refinement indicates that Al preferentially occupies M1 (= 0.692Al + 0.308Fe) over M2 (= 0.516Al + 0.484Fe). The substitution of the majority of Fe in mandarinoite by Al results in a significant reduction in its unit-cell volume from 1313.4 Å3 to 1250.21(6) Å3 for bernardevansite. The discovery of bernardevansite begs the question whether the Fe3+ end-member, Fe3+2(SeO3)3⋅6H2O, has two polymorphs as well, one with P21/c symmetry, as for mandarinoite and the other P$bar{6}$2c, as for alfredopetrovite.","PeriodicalId":18618,"journal":{"name":"Mineralogical Magazine","volume":"87 1","pages":"407 - 414"},"PeriodicalIF":2.7,"publicationDate":"2023-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41596861","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":"Silesiaite, ideally Ca2Fe3+Sn(Si2O7)(Si2O6OH), a new species in the kristiansenite group: crystal chemistry and structure of holotype silesiaite from Szklarska Poręba, Poland, and Sc-free silesiaite from Häiviäntien, Finland","authors":"A. Pieczka, S. Zelek-Pogudz, B. Gołębiowska, K. Stadnicka, R. Kristiansen","doi":"10.1180/mgm.2023.5","DOIUrl":"https://doi.org/10.1180/mgm.2023.5","url":null,"abstract":"Abstract Two silesiaite crystals, one from Szklarska Poręba, Poland (type locality), and the other from Häiviäntien, Finland, were studied with electron-probe microanalysis, Raman spectroscopy and single-crystal X-ray diffraction. The crystals have the following compositions normalised to 13 O2– + 1 (OH)– anions: Ca2.001(2)[(Sn1.105(6)Zr0.009(1))Σ1.114(Fe3+0.523(78)Sc0.185(62)Al0.070(14))Σ0.779(Fe2+0.065(12)Mn2+0.041(5)Mg0.003(3))Σ0.110]Σ2.003(Si3.997(2)O13OH), and Ca2.006(8)[(Sn1.110(18)Ti0.006(3))Σ1.107(Fe3+0.648(50)Al0.063(11))Σ0.710(Fe2+0.140(30)Mn2+0.011(3)Mg0.005(2))Σ0.155(Nb0.020(6)Ta0.011(3))Σ0.040]Σ2.009(Si3.991(14)O13OH), respectively. The structure of the crystals was refined in the triclinic system with unconventional space-group symmetry C1 to R1 = 2.02% and 3.56%, respectively. The unit cells were found to be a = 10.0080(2), b = 8.3622(1), c = 13.2994(2) Å, α = 89.987(1), β = 109.095(2), γ = 89.978(1)° and V = 1051.77(3) Å3 for silesiaite from Szklarska Poręba, and a = 9.9985(3), b = 8.3446(2), c = 13.2760(4) Å, α = 89.986(3), β = 109.122(2), γ = 90.020(2)° and V = 1046.55(5) Å3 for silesiaite from Häiviäntien. In both crystals, the Ca sites are occupied solely by calcium and Si sites by silicon atoms. Optimised occupancies of the four M sites indicated slightly different site fillings. In the Szklarska Poręba silesiaite, the M1 site is predominantly occupied by trivalent Fe + Sc and the M2–M4 sites by Sn. In contrast, in the Häiviäntien silesiaite, the M1–M3 sites are Sn-dominant, while Fe3+ predominantly occupies the M4 site. The differences can be considered a result of an evolution of the M1–M4 site occupancies following a decrease of the distance. Among the minerals of the kristiansenite group, Sc-free silesiaite from the Häiviäntien pegmatite has the smallest average radius of M-site cations and a unit-cell volume that increases proportionally to the (Fe2+ ± Sc) content. The hydrogen atoms form moderate hydrogen bonds between disilicate groups (Si2O7 and Si2O6OH) linked in rows along [101], indicating the presence of one hydroxyl in the formula calculated for Z = 4. All three kristiansenite-group species, i.e. silesiaite, kozłowskiite and kristiansenite, are isostructural.","PeriodicalId":18618,"journal":{"name":"Mineralogical Magazine","volume":"87 1","pages":"271 - 283"},"PeriodicalIF":2.7,"publicationDate":"2023-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41648164","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":"Crystal chemistry of turkestanite, Dara-i-Pioz massif, Tajikistan","authors":"E. Kaneva, T. Radomskaya, O. Belozerova, R. Shendrik","doi":"10.1180/mgm.2023.3","DOIUrl":"https://doi.org/10.1180/mgm.2023.3","url":null,"abstract":"Abstract The results of combined single-crystal X-ray diffraction, electron probe microanalysis, Fourier microspectroscopy, and photoluminescence spectroscopy study of crystals of turkestanite from the Dara-i-Pioz deposit, Tien-Shan Mountains, Tajikistan are reported. It is a single-layer sheet silicate belonging to the ekanite group with a steacyite structural type. Averaged major-element analysis provided (wt.%): K2O 4.13(6), CaO 8.1(1), Na2O 2.3(1), ThO2 25.8(4), UO2 3.6(4) and SiO2 55.9(1). The averaged crystal-chemical formula for the studied turkestanite is (Th0.84U0.12)Σ0.96(Ca1.24Na0.65)Σ1.89(K0.75☐0.25)Σ1.00Si8O19.72(OH)0.28. Single-crystal structural refinement of turkestanite gave tetragonal, space group P4/mcc, a = 7.5708(3) Å, c = 14.7300(11) Å, V = 844.27(6) Å3 and Z = 2. Luminescence of the uranyl ion (UO2)2+ is observed in turkestanite. In the excitation spectrum, the bands corresponding to a charge transfer transition from the 2p states of the ligand to the 5f state of uranium were found.","PeriodicalId":18618,"journal":{"name":"Mineralogical Magazine","volume":"87 1","pages":"252 - 261"},"PeriodicalIF":2.7,"publicationDate":"2023-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48521325","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":"Ferro-ferri-katophorite, a new clinoamphibole from the silicocarbonatite dykes in Sierra de Maz, La Rioja, Argentina","authors":"F. Colombo, J. Rius, E. Molins, Héctor Biglia, M. A. Galliski, M. F. Márquez-Zavalía, E. Baldo, Agustín Kriscautzky","doi":"10.1180/mgm.2023.2","DOIUrl":"https://doi.org/10.1180/mgm.2023.2","url":null,"abstract":"Abstract Ferro-ferri-katophorite (IMA2016–008), ideally Na(NaCa)(Fe2+4Fe3+)(Si7Al)O22(OH)2, was found as xenocrysts up to 3 cm long and replacement rims around aegirine–augite in silicocarbonatite dykes cropping out in the Sierra de Maz, La Rioja province, NW Argentina. Ferro-ferri-katophorite is black and has vitreous lustre and a pale green streak. The new mineral is brittle, with perfect {110} cleavage and has a Mohs hardness of 6. The measured density is 3.32(1) g/cm3. In plane-polarised light it is strongly pleochroic, X = light greenish brown, Y = dark greyish brown and Z = dark greyish olive green. Absorption (very strong) is Z > Y > X. The orientation is: Z ∥ b, and X forms a small angle with [001]. Ferro-ferri-katophorite is biaxial (–), with α = 1.688(3), β = 1.697(3), γ = 1.698(3) and 2V(calc) = 36.7°. It is monoclinic, space group C2/m, a = 9.8270(7), b = 18.0300(8), c = 5.316(4) Å, β = 104.626(4)°, V = 911.4(6) Å3 and Z = 2. The strongest five lines in the powder X-ray diffraction pattern [d in Å (I)(hkl)] are: 8.416(100)(110), 3.135(50)(310), 2.815(26)(330), 2.720(18)(151) and 1.4422(15)($bar{6}$61). The chemical composition is SiO2 43.08, TiO2 2.76, ZrO2 0.15, Al2O3 8.76, V2O3 0.07, Fe2O3 9.28, FeO 13.85, MnO 0.43, MgO 6.88, CaO 6.58, ZnO 0.06, Na2O 5.55, K2O 1.18, Cl 0.01, H2O calc 1.36, total 99.95 wt.%. The formula unit (confirmed by single-crystal structural analysis) is (Na0.74K0.23)Σ0.97(Ca1.08Na0.91Mn0.01)Σ2.00(Fe2+1.78Mg1.57Fe3+1.07Ti4+0.32Al0.19Mn2+0.04Zr0.01V3+0.01Zn0.01)Σ5.00(Si6.61Al1.39)Σ8.00O22(OH1.59O0.61)Σ2.00. Aluminium is strongly ordered at the T(1) site. Ferro-ferri-katophorite is the 9th species carrying the katophorite root name and is related to katophorite by the Fe2+ + Fe3+ → Mg2+ + Al3+ substitution. Type material was deposited at the Museo de Mineralogía “Stelzner”, Universidad Nacional de Córdoba, Argentina, under catalogue number MS003341.","PeriodicalId":18618,"journal":{"name":"Mineralogical Magazine","volume":"87 1","pages":"324 - 330"},"PeriodicalIF":2.7,"publicationDate":"2023-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41945990","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":"Synthesis of Fe-deficient eudialyte analogues: Relationships between the composition of the reaction system and crystal-chemical features of the products","authors":"T. Kovalskaya, V. Ermolaeva, N. Chukanov, D. Varlamov, Georgy A. Kovalskiy, E. Zakharchenko, G. M. Kalinin, Korney D. Chaichuk","doi":"10.1180/mgm.2023.1","DOIUrl":"https://doi.org/10.1180/mgm.2023.1","url":null,"abstract":"Abstract Eudialyte-related compounds have been synthesised hydrothermally at T = 600°C and P = 2 kbar from a stoichiometric mixture of Na2CO3, CaO, Fe2O3, ZrOCl2 and SiO2 using the Na:Ca:Fe:Zr:Si ratios corresponding to the eudialyte end-member Na15Ca6Fe3Zr3Si(Si25O73)(OH)Cl2⋅H2O, in the presence of 1 M aqueous solutions of NaCl and NaF. The synthesis was carried out in platinum ampoules over 10 days. Natural raslakite (a Ca-deficient member of the eudialyte group) was used as a seed and added in amounts corresponding to 2 wt.% of the whole charge. The products were characterised by powder X-ray diffraction, IR and Raman spectroscopy, morphological features, and electron probe microanalyses. In experiments with NaCl, almost pure eudialyte-type compounds were obtained. Synthesis in the presence of a NaF solution resulted in the formation of a F-dominant eudialyte-type compound related to raslakite as the main product and aegirine, vlasovite and lalondeite as by-products. All synthesised eudialyte-type compounds are Zr-rich and Fe-deficient, similar to eudialyte-group minerals from hyperagpaitic rocks related to foyaites. The increased NaCl contents in the reaction system results in increased Ca content in the synthesised eudialyte-related compounds. The crystal-chemical formulae of the synthesised eudialyte-type compounds are derived based on general regularities established earlier for eudialyte-group minerals.","PeriodicalId":18618,"journal":{"name":"Mineralogical Magazine","volume":"87 1","pages":"233 - 240"},"PeriodicalIF":2.7,"publicationDate":"2023-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48356931","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":"Newsletter 70","authors":"Ritsuro Miyawaki, Frédéric Hatert, Marco Pasero, Stuart J. Mills","doi":"10.1180/mgm.2022.135","DOIUrl":"https://doi.org/10.1180/mgm.2022.135","url":null,"abstract":"Ritsuro Miyawaki, (Chairman, CNMNC)1, Frédéric Hatert, (Vice-Chairman, CNMNC)2, Marco Pasero, (Vice-Chairman, CNMNC)3 and Stuart J. Mills, (Secretary, CNMNC)4 1 Department of Geology, National Museum of Nature and Science, 4-1-1 Amakubo, Tsukuba 305-0005, Japan – miyawaki@kahaku.go.jp; 2 Laboratoire de Minéralogie, Université de Liège, Bâtiment B18, Sart Tilman, 4000 Liège, Belgium – fhatert@uliege.be; 3 Dipartimento di Scienze della Terra, Università di Pisa, Via Santa Maria 53, 56126 Pisa, Italy – marco.pasero@unipi.it; and 4 Geosciences, Museums Victoria, PO Box 666, Melbourne, Victoria 3001, Australia – smills@museum. vic.gov.au","PeriodicalId":18618,"journal":{"name":"Mineralogical Magazine","volume":"87 1","pages":"160 - 168"},"PeriodicalIF":2.7,"publicationDate":"2023-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47134938","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":"Alumolukrahnite, CaCu2+Al(AsO4)2(OH)(H2O), the aluminium analogue of lukrahnite from the Jote mine, Copiapó Province, Chile","authors":"A. R. Kampf, S. Mills, B. Nash, M. Dini, A. A. M. Donoso","doi":"10.1180/mgm.2022.142","DOIUrl":"https://doi.org/10.1180/mgm.2022.142","url":null,"abstract":"Abstract The new mineral alumolukrahnite (IMA2022–059), CaCu2+Al(AsO4)2(OH)(H2O), was found at the Jote mine, Copiapó Province, Chile, where it is a secondary alteration phase associated with conichalcite, coronadite, gypsum, olivenite, pharmacosiderite, rruffite and scorodite. Alumolukrahnite occurs as crude diamond-shaped tablets up to ~0.1 mm, intergrown in crude spherical aggregates. Crystals are apple green and transparent to translucent, with vitreous lustre and a white streak. The Mohs hardness is 3½. The mineral is brittle with irregular fracture and no cleavage. The calculated density is 4.094 g cm–3. Optically, alumolukrahnite is biaxial (+) with α = 1.73(1), β = 1.74(1) and γ = 1.76(1) (white light). The empirical formula, determined from electron microprobe analyses, is Ca1.01(Cu0.92Zn0.13)Σ1.05(Al0.96Fe0.01)Σ0.97(As0.985O4)2(OH)0.88(H2O)1.12. Alumolukrahnite is triclinic, P$bar{1}$, a = 5.343(5), b = 5.501(5), c = 7.329(5) Å, α = 67.72(2), β = 69.06(2), γ = 69.42(2)°, V = 180.3(3) Å3 and Z = 1. Alumolukrahnite is a member of the tsumcorite group and is the Al analogue of lukrahnite.","PeriodicalId":18618,"journal":{"name":"Mineralogical Magazine","volume":"87 1","pages":"465 - 469"},"PeriodicalIF":2.7,"publicationDate":"2022-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44486738","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":"Crystal structures of rhodium-containing erlichmanite–laurite solid solutions (Os1–x–yRuxRhyS2: x = 0.09–0.60, y = 0.07–0.10) with unique compositional dependence","authors":"Ginga Kitahara, A. Yoshiasa, S. Ishimaru, Kunihisa Terai, M. Tokuda, D. Nishio–Hamane, Takahiro Tanaka, K. Sugiyama","doi":"10.1180/mgm.2022.139","DOIUrl":"https://doi.org/10.1180/mgm.2022.139","url":null,"abstract":"Abstract Rh-rich and Ir-poor erlichmanite–laurite OsS2–RuS2 solid solutions have been discovered at placers in Haraigawa, Misato-machi, Kumamoto, Japan. Microprobe analysis was performed to identify solid solutions containing few sub-components other than Rh. Approximately 10 at.% Rh was found to be present in the solid-solution samples. Structural refinement was performed using four natural samples: Os0.32Ru0.61Rh0.07S2, Os0.49Ru0.43Rh0.08S2, Os0.58Ru0.33Rh0.08S2 and Os0.81Ru0.09Rh0.10S2. The unit-cell parameters for the solid solutions containing Rh from Haraigawa varied from 5.61826(6) to 5.63142(8) Å. The (Os, Ru, Rh)–S distances in the Os1–x–yRuxRhyS2 system were almost constant with a small variation of 0.001 Å. Conversely, the S–S distances varied significantly, with variations approaching 0.1 Å. Rh substitution of Os rather than Ru had a larger impact on the crystal structure. The atomic displacement ellipsoid of both cations and anions was almost spherical, and no elongation along the M–S and S–S bond directions was observed. The bulk Debye temperatures were estimated from the Debye–Waller factor for the sulfide site. The bulk Debye temperatures of pure OsS2 and RuS2 were 688 K and 661 K, respectively, which suggests that the melting point of erlichmanite is higher than that of laurite. The high Debye temperature of OsS2 is inconsistent with the crystallisation of laurite prior to erlichmanite from the primitive magma, which suggests that $f_{rm S_2}$, rather than temperature, is the main cause of the known crystallisation order. The presence of several percent Rh has a significant effect on the thermal stability of OsS2 and lowers the melting point of the erlichmanite solid solution compared to that of the laurite solid solution.","PeriodicalId":18618,"journal":{"name":"Mineralogical Magazine","volume":"87 1","pages":"396 - 406"},"PeriodicalIF":2.7,"publicationDate":"2022-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43546643","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}