The Canadian Mineralogist最新文献

{"title":"Lauraniite, Cu6Cd2(SO4)2(OH)12·5H2O, a New Copper Cadmium Sulfate Mineral from the Laurani Mine, Bolivia","authors":"P. Elliott, A. R. Kampf","doi":"10.3749/canmin.2200014","DOIUrl":"https://doi.org/10.3749/canmin.2200014","url":null,"abstract":"\u0000 Lauraniite, Cu6Cd2(SO4)2(OH)12·5H2O, is a new mineral from the Laurani Mine, Aroma Province, La Paz Department, Bolivia, where it is found as a secondary mineral associated with serpierite and brochantite, on a matrix consisting of tennantite and chalcocite. Lauraniite occurs as bladed crystals up to 110 μm in length. Crystals are pale blue and transparent, with a vitreous luster and a white streak. Fracture is uneven. Cleavage is perfect on {100}. The calculated density is 3.40 g/cm3 based on the empirical formula. Optically, lauraniite is uniaxial (+) with α = 1.637(3), β = 1.638(3), γ = 1.638(3) (white light), 2V = 20(2)°, and orientation Z ≈ a. The empirical formula, based on data obtained from electron microprobe analysis, is Cu6.13(Cd1.62Zn0.24)(SO4)1.96(OH12.03Cl0.05)12.08·5.08H2O. Lauraniite is monoclinic, P21/c, a = 7.3200(15), b = 25.424(5), c = 11.283(2) Å, β = 91.62(3)°, V = 2099.0(7) Å3, and Z = 4. The crystal structure, determined using single-crystal data obtained using synchrotron radiation, refined to R1 = 0.0468% for 5999 observed reflections with Fo > 4σ(Fo). It is characterized by undulating, brucite-like sheets consisting of seven Cuϕ6 (ϕ: O2–, OH–, H2O) octahedra and two Cd(OH)6(H2O) polyhedra. Sheets are decorated on one side by corner-sharing SO4 tetrahedra. Linkages between adjacent sheets are provided by H-bonds.","PeriodicalId":134244,"journal":{"name":"The Canadian Mineralogist","volume":"271 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134332421","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":"Matthiasweilite, PbTe4+O3, a New Tellurite Mineral from the Delamar Mine, Lincoln County, Nevada, USA","authors":"A. R. Kampf, Owen P. Missen, S. Mills, Chiu‐Shun Ma, R. Housley, Marek Chorazewicz, J. Marty, M. Coolbaugh, Koichi Momma","doi":"10.3749/canmin.2200015","DOIUrl":"https://doi.org/10.3749/canmin.2200015","url":null,"abstract":"\u0000 Matthiasweilite (IMA2021-069), Pb2+Te4+O3, is a new mineral discovered at the Delamar mine, Lincoln County, Nevada, USA. It is a secondary mineral, associated with adanite, choloalite, northstarite, and other oxysalts in a quartz-rich matrix, that developed in an altered primary ore along with altaite, tetrahedrite-(Zn), native gold, and other sulfides and selenides. The mineral occurs as tightly intergrown masses of light yellow crystals. The streak is white, luster is adamantine, Mohs hardness is 2½, tenacity is brittle, and fracture is conchoidal; no obvious cleavage is present. The calculated density is 7.282 g/cm3 for the empirical formula. Data from electron probe microanalysis and assuming O = 3 gives the empirical formula Pb0.99Te4+1.01O3. Matthiasweilite is triclinic, space group P, with cell parameters a = 7.0256(4), b = 10.6345(6), c = 11.9965(8) Å, α = 78.513(6), β = 83.104(6), γ = 84.083(6)°, V = 869.10(9) Å3, and Z = 10. The crystal structure (R1 = 0.0523 for 3416 I > 2σI reflections) consists of Te4+O3 trigonal pyramids that are linked via relatively short (<2.6 Å) Pb–O bonds to form a framework.","PeriodicalId":134244,"journal":{"name":"The Canadian Mineralogist","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133080534","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":"Mengeite, Ba(Mg,Mn2+)Mn3+4(PO4)4(OH)4·4H2O, a New Mineral from the Spring Creek Mine, South Australia, Australia","authors":"P. Elliott","doi":"10.3749/canmin.2100041","DOIUrl":"https://doi.org/10.3749/canmin.2100041","url":null,"abstract":"\u0000 Mengeite, Ba(Mg,Mn2+)Mn3+4(PO4)4(OH)4·4H2O, is a new mineral from the Spring Creek copper mine, near Wilmington, South Australia, Australia, where it occurs as dark orange-red masses to 0.8 mm across in a quartz matrix. The streak is pale salmon pink and the luster is vitreous. Mengeite is non-fluorescent and the Mohs hardness is ∼3. The measured density is 3.40 g/cm3 and the calculated density is 3.43 g/cm3. Mengeite is biaxial (–) with α = 1.757(4), β = 1.776(4), γ = 1.781(4) measured in white light. Electron microprobe analyses results give the empirical formula, based on 24 O apfu: Ba1.09(Mg0.58Mn2+0.26Cu0.10Al0.02Na0.01Ca0.01□0.09)Σ1.07Mn3+3.88(PO4)4.07(OH)3.52·4.13H2O. The idealized formula is Ba(Mg,Mn2+)Mn3+4(PO4)4(OH)4·4H2O. Mengeite is triclinic, space group , with a = 5.4262(11), b = 5.4274(11), c = 16.387(3) Å, α = 87.61(3), β = 98.97(3), γ = 110.56(3)°, V = 446.28(16) Å3, and Z = 1. The crystal structure of mengeite was solved using synchrotron single-crystal X-ray diffraction data and refined to R1 = 0.0453 for 2115 observed reflections with F0 > 4σ(F0). It is based on [(M2(OH)2(AsO4)2] sheets that are linked in the c-direction alternately by [M3(H2O)4O2] octahedra and by BaO10 polyhedra.","PeriodicalId":134244,"journal":{"name":"The Canadian Mineralogist","volume":"99 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129322240","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 Taxonomy of Mineral Occurrence Rarity and Endemicity","authors":"L. Gavryliv, V. Ponomar, Marko Bermanec, M. Putiš","doi":"10.3749/canmin.2200010","DOIUrl":"https://doi.org/10.3749/canmin.2200010","url":null,"abstract":"\u0000 Nearly a half of known IMA-approved minerals (as of November 2021) are reported from four localities or fewer and so may be considered rare mineral species. These minerals form a continuum with more common species (e.g., rock-forming minerals), all of which constitute important constituents of Earth and contributors to its dynamics. To better understand the taxonomy of mineral rarity, evaluations have been made on the basis of k-means clustering and kernel density estimation of one-dimensional data on mineral occurrence metrics. Results from second- and third-degree polynomial regression analyses indicate the presence of a divergence between the observed number of endemic minerals discovered since 2000 and those that are likely to represent “true” endemic species. The symmetry index, calculated using the approach of Urusov for each rarity cluster, reveals a gradual decrease from ubiquitous to endemic from 0.64 to 0.47. A network analysis of element co-occurrences within each rarity cluster suggests the existence of at least three different communities having similar geochemical affinities; the latter may reflect the relative abundance of minerals their elements tend to form. The analysis of element co-occurrence matrices within each group indicates that crustal abundance is not the only factor controlling the total number of minerals each element tends to form. Other significant factors include: (1) the geochemical affinity to the principal element in the group (i.e., sulfur for chalcophile and oxygen for lithophile elements) and (2) dispersion of the principal element through geochemical processes. There is a positive correlation between the lithophile element group's abundance in the Earth's crust and the number of common minerals they tend to form, but a negative correlation with the number of rare species.","PeriodicalId":134244,"journal":{"name":"The Canadian Mineralogist","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130584254","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":"Dondoellite, Ca2Fe(PO4)2·2H2O, a New Mineral Species Polymorphic with Messelite, from Rapid Creek, Yukon, Canada","authors":"Hexiong Yang, R. Gibbs, J. McGlasson, R. Jenkins, R. Downs","doi":"10.3749/canmin.2200013","DOIUrl":"https://doi.org/10.3749/canmin.2200013","url":null,"abstract":"\u0000 A new mineral species, dondoellite, ideally Ca2Fe(PO4)2·2H2O, was found in the Grizzly Bear Creek, Dawson mining district, Yukon, Canada. It is polymorphic with messelite, a member of the fairfieldite group. Dondoellite occurs as spherical aggregates (diameters up to 2 cm) of radiating bladed crystals. Associated minerals include hydroxylapatite, siderite, and quartz. No twinning or parting is observed. The mineral is colorless to pale yellow in transmitted light, is transparent with white streak, and has vitreous luster. It is brittle and has a Mohs hardness of 3½–4, with perfect cleavage on {001}. The measured and calculated densities are 3.14(5) and 3.15 g/cm3, respectively. Optically, dondoellite is biaxial (+), with α = 1.649(5), β = 1.654(5), γ = 1.672(5) (white light), 2V (meas.) = 55(2)°, 2V (calc.) = 58°. An electron probe microanalysis yields an empirical formula (based on 10 O apfu) Ca1.99(Fe0.89Mg0.13Mn0.01)Σ1.03(P1.00O4)2·2H2O, which can be simplified to Ca2(Fe2+,Mg,Mn2+)(PO4)2·2H2O.\u0000 Dondoellite is triclinic, space group P, a = 5.4830(2), b = 5.7431(2), c = 13.0107(5) Å, α = 98.772(2), β = 96.209(2), γ = 108.452(2)°, V = 378.71(2) Å3, and Z = 2. The crystal structure of dondoellite is characterized by isolated FeO4(H2O)2 octahedra that are linked by corner-sharing with PO4 tetrahedra to form so-called kröhnkite-type [Fe(PO4)2(H2O)2]2– chains along [100], similar to that observed in messelite. These chains are connected to one another by large Ca2+ cations and H bonds to form layers parallel to (001). The layers are further linked together by Ca–O and H bonds. However, unlike messelite, the crystal structure of dondoellite contains two symmetrically independent PO4 tetrahedra (P1O4 and P2O4) and two distinct CaO7(H2O) polyhedra (Ca1 and Ca2). The kröhnkite-type chains in dondoellite are constructed with P1O4 tetrahedra on one side and P2O4 tetrahedra on the other. Topologically, the dondoellite structure can be considered a combination of the collinsite and messelite structures alternating along [001], thus representing a new structure type for minerals with kröhnkite-type chains. The discovery of dondoellite raises the question as to whether polymorphs of fairfieldite, Ca2Mn2+(PO4)2·2H2O, or collinsite, Ca2Mg(PO4)2·2H2O, might also be found in nature.","PeriodicalId":134244,"journal":{"name":"The Canadian Mineralogist","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127564726","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":"Nitroplumbite, [Pb4(OH)4](NO3)4, a New Mineral with Cubane-Like [Pb4(OH)4]4+ Clusters from the Burro Mine, San Miguel County, Colorado, USA","authors":"A. R. Kampf, John M. Hughes, B. Nash, J. Marty","doi":"10.3749/canmin.2200009","DOIUrl":"https://doi.org/10.3749/canmin.2200009","url":null,"abstract":"\u0000 Nitroplumbite (IMA2021-045a), [Pb4(OH)4](NO3)4, is a new mineral discovered at the Burro mine, Slick Rock district, San Miguel County, Colorado, USA. It occurs in a secondary efflorescent assemblage on asphaltite and montroseite- and corvusite-bearing sandstone in association with baryte, chalcomenite, and volborthite. The mineral forms as brown equant (pseudocubic) or colorless bladed crystals. The streak is white, luster is vitreous to greasy, Mohs hardness is 2½, tenacity is brittle, and fracture is conchoidal. Nitroplumbite is optically biaxial (–) with α = 1.790(5), β =1.820 (est.), and γ = 1.823 (est.) (white light); 2Vmeas = 35(1)°; optical orientation: Z = b; nonpleochroic. The calculated density is 5.297 g/cm3 for the empirical formula. Electron probe microanalysis provided the empirical formula Pb4.18(OH)4(N0.98O3)4. Nitroplumbite is monoclinic, space group Ia, a = 18.3471(7), b = 17.3057(4), c = 18.6698(8) Å, β = 91.872(3)°, V = 5924.7(4) Å3, and Z = 16. The crystal structure (R1 = 0.0509 for 11161 I > 2σI reflections) is the same as that previously determined for its synthetic analogue. It consists of isolated, internally bonded cubane-like [Pb4(OH)4]4+ clusters and isolated (NO3)– groups that are linked together by long Pb–O bonds and hydrogen bonds.","PeriodicalId":134244,"journal":{"name":"The Canadian Mineralogist","volume":"70 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133177913","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":"Håleniusite-(Ce), CeOF, the Ce Analogue of Håleniusite-(La) from the Água de Pau Volcano, Sãn Miguel Island, Azores District, Portugal","authors":"A. Kampf, Chi Ma, Luigi Chiappino","doi":"10.3749/canmin.2200002","DOIUrl":"https://doi.org/10.3749/canmin.2200002","url":null,"abstract":"\u0000 Håleniusite-(Ce) (IMA2021-042), CeOF, is a new mineral discovered in ejectum from the Água de Pau volcano, Sãn Miguel Island, Azores District, Portugal. It occurs as opaque, cream-colored, fine-grained pseudomorphic replacements of hexagonal tablets of bastnäsite-(Ce). It is associated with astrophyllite and fluornatropyrochlore in a matrix composed mainly of albite, quartz, and aegirine. The mineral has a white streak and a calculated density of 5.890 g/cm3 for the empirical formula. The strongest powder diffraction lines are [dobsÅ(Iobs)(hkl)]: 3.247(100)(111), 2.840(31)(200), 2.004(46)(220), and 1.705(42)(311). Electron probe microanalysis provided the empirical formula (Ce0.41La0.21Sm0.15Nd0.04Eu0.03Ca0.02Y0.02Dy0.02Gd0.01)Σ0.91(O0.70F0.30)F1.00. Håleniusite-(Ce) has a fluorite-type structure, space group Fmm, with a = 5.6597(10) Å and V = 181.29(10) Å3 (Z = 4).","PeriodicalId":134244,"journal":{"name":"The Canadian Mineralogist","volume":"95 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114411303","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":"Development of Tourmaline-Bearing Lithologies of the Peraluminous Tusaquillas Composite Granitic Batholith, NW Argentina: Evidence from Quartz and Tourmaline","authors":"D. Henry, E. Zappettini, B. Dutrow","doi":"10.3749/canmin.2100047","DOIUrl":"https://doi.org/10.3749/canmin.2100047","url":null,"abstract":"\u0000 Textural and chemical characteristics of quartz and tourmaline found in tourmaline-rich orbicules, greisens, pegmatites, and tourmalinite segregations associated with the peraluminous leucogranitic Tusaquillas Batholith Complex of northwest Argentina exhibit both magmatic and hydrothermal features. Imaging of quartz by optical cathodoluminescence and scanning electron microscopy cathodoluminescence shows three stages of development. Stage-1 quartz, considered magmatic, develops as large grains in pegmatites that have optical cathodoluminescence homogeneity; as anhedral relict grains partially replaced by stage-2 hydrothermal quartz in tourmalinite segregations, orbicules, and greisens; and as idiomorphic grains with irregularly spaced oscillatory zoning seen in scanning electron microscopy cathodoluminescence in orbicules. Stage-2 quartz, interpreted as hydrothermal, partially replaces stage-1 quartz and generation-1 tourmaline in most lithologies. Stage-3 quartz, a late hydrothermal stage, occurs in all lithologies as weakly luminescing quartz in healed quartz fractures with abundant fluid inclusions, commonly associated with the crystallization of irregular late-stage tourmaline.\u0000 Multiple generations of tourmaline span magmatic to hydrothermal phases of development. In all lithologies, generation-1 tourmaline is compositionally similar: highly aluminous (range of average values of Altotal = 6.31–6.95 apfu), markedly Fe- and X□-rich (XMg = 0.01–0.17, X□= 0.21–0.51), and having variable F and WO (F = 0.00–0.57 apfu, WO = 0.00–0.40). Generation-1 tourmaline is interpreted as magmatic with compositions reflecting the chemical environment of the host lithologies and with compositional zoning patterns characteristic of both closed- and open-system behavior, possibly related to the transition to subsolidus conditions. Similar to generation-1 tourmaline, later-stage generations-2 and -3 tourmaline compositions are highly aluminous (range of average values of Altotal = 6.38–6.79 apfu), markedly Fe- and X□-rich (XMg = 0.00–0.20, X□= 0.28–0.40), and variably F- and WO-enriched (F = 0.07–0.57 apfu, WO = 0.00–0.31), but notably poorer in Ca and Ti (<0.01 apfu). The later-stage tourmaline is considered to have developed during the subsolidus hydrothermal conditions. External chemical contributions to tourmaline compositions from the country rocks appear to be minor to nonexistent. The X-site and W-site occupancies of the late-generation tourmaline implies subsolidus invasive alkaline, saline aqueous fluids with high Na but minimal Ca contents derived from the crystallizing leucogranites and related rocks across the solidus-to-subsolidus transition.","PeriodicalId":134244,"journal":{"name":"The Canadian Mineralogist","volume":"205 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123255800","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":"Magnetic Petrology of Crust- and Mantle-Derived Mesoarchean Ourilândia Granitoids, Carajás Mineral Province, Brazil","authors":"A. C. do Nascimento, D. C. de Oliveira, L. R. da Silva, Raquel Sacramento","doi":"10.3749/canmin.2100026","DOIUrl":"https://doi.org/10.3749/canmin.2100026","url":null,"abstract":"\u0000 This paper presents a detailed study of magnetic petrology in crust- and mantle-derived Mesoarchean granitoids (2.92–2.88 Ga) from the Ourilândia do Norte area, which is situated in the midwestern Carajás Mineral Province, southeastern Amazonian Craton (northern Brazil). The textural aspects of opaque minerals and their relation to magnetic susceptibility (MS) were combined with the results of previous works that involve whole-rock geochemistry and mineral chemistry data to discuss the formation conditions and to correlate the MS values and opaque mineral content with the crustal input related to the source of these rocks. The Ourilândia granitoids can be divided into the following three lithological associations: (1) potassic granites represented by biotite monzogranites and high-Ti granodiorites, which both host tonalite-trondhjemite-granodiorite (TTG) affinity tonalitic xenoliths; (2) sanukitoids formed by granodiorites (equi- to heterogranular and porphyritic), with minor occurrences of tonalite, quartz monzodiorite, quartz diorite, and mafic microgranular enclaves; and (3) TTG-affinity porphyritic trondhjemite, which is represented by a small, slightly deformed stock. The cumulative frequency curve from the MS data defines three main magnetic populations as follows: (1) population A is characterized by low MS values (0.05 × 10–3 to 0.59 × 10–3 SI) formed by sanukitoid and trondhjemite rocks, which contain rare opaque minerals; (2) population B is defined by moderate MS values (0.70 × 10–3 to 1.24 × 10–3 SI) wherein sanukitoids predominate over the potassic granites while ilmenite prevails in relation to magnetite; (3) population C is represented by high MS values (1.33 × 10–3 to 17.0 × 10–3 SI) in which potassic granites and high-Ti granodiorites are predominant, in addition to the porphyritic and heterogranular sanukitoids. The Fe/(Fe + Mg) ratios in whole rock, biotite, and amphibole indicate high redox conditions for the sanukitoids and potassic granites, which are mostly above the nickel-nickel oxide (NNO) buffer (+0.5 < NNO < +1.9) and at or slightly below the NNO for the TTG-affinity trondhjemite (–0.5 < NNO < +1.0). The variation in the opaque mineral content (especially magnetite) explains in the first instance the magnetic behavior of these rocks. Furthermore, our results not only suggest that the oxidation states recorded in these granitoids are associated with the nature of their sources, but also suggest that unlike the depleted mantle (reduced in nature), the continental crust (monzogranite source) and subcontinental lithospheric mantle (the source of the sanukitoids and high-Ti granodiorite) are oxidized, while the oceanic crust (trondhjemite source) is moderately oxidized. The low MS values and the scarcity of magnetite reported for the equigranular sanukitoids and trondhjemite can be attributed to the variations in crustal input (crustal anatexis and/or mantle enrichment) in magmas that can change the overall fO2 and thereb","PeriodicalId":134244,"journal":{"name":"The Canadian Mineralogist","volume":"102 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121397779","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":"CRYSTAL-CHEMICAL OBSERVATIONS AND THE RELATION BETWEEN SODIUM AND WATER IN DIFFERENT BERYL VARIETIES","authors":"Rhiana E. Henry, L. Groat, R. Evans, J. Cempírek, R. Škoda","doi":"10.1130/abs/2021am-366554","DOIUrl":"https://doi.org/10.1130/abs/2021am-366554","url":null,"abstract":"\u0000 Beryl (Be3Al2Si6O18) is a well-known mineral, most famously in its vivid green form of emerald, but also as a range of other colors. Prominent varieties of beryl aside from emerald include aquamarine, red beryl, heliodor, goshenite, and morganite. There has not been a significant amount of research dedicated to comparing the crystal-chemical differences among the varieties of beryl except in determining chromophoric cations. While the H2O content within structural channels of emerald has been explored, and the H2O content of individual beryl specimens has been studied, there has not yet been a study comparing the H2O content systematically across beryl varieties. In this study we consider single-crystal X-ray diffraction data and electron probe microanalyses of 80 beryl specimens of six primary varieties, to compare and contrast their crystal chemistry. Beryl cation substitutions are dominantly coupled substitutions that require Na to enter a structural channel site. The results indicate that with increasing Na content beryl varieties diverge into two groups, characterized by substitutions at octahedral or tetrahedral sites, and that the dominant overall cation substitutions in each beryl variety tend to be different in more than just their chromophores. We find that the relation between Na and H2O content in beryl is consistent for beryl with significant Na content, but not among beryl with low Na content. Natural red beryl is found to be anhydrous, and heliodor has Na content too low to reliably determine H2O content from measured Na. We determined equations and recommendations to relate the Na and H2O content in emerald, aquamarine, goshenite, and morganite from a crystallographic perspective that is applicable to beryl chemistry measured by other means. This research will help guide future beryl studies in classifying beryl variety by chemistry and structure and allow the calculation of H2O content in a range of beryl varieties from easily measured Na content instead of requiring the use of expensive or destructive methods.","PeriodicalId":134244,"journal":{"name":"The Canadian Mineralogist","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128571385","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}