| 1. |
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| 2. |
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| 3. |
- Bonazzi, Paola, et al.
(författare)
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Multi-analytical approach to solve the puzzle of an allanite-subgroup mineral from Kesebol, Vastra Gotaland, Sweden
- 2009
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Ingår i: American Mineralogist. - : Mineralogical Society of America. - 0003-004X .- 1945-3027. ; 94:1, s. 121-134
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Tidskriftsartikel (refereegranskat)abstract
- Dark-brownish. euhedral crystals of an "allanite-like" mineral occur in a hematite-impregnated Mn-silicate rock at Kesebol, Vastra Gotaland, Sweden, associated with gasparite-(Ce), chernovite-(Y), rhodonite, andradite, manganoan calcite, and quartz. A structural study was carried out on single crystals-untreated, heated in air, and heated under inert atmosphere-combined with Mossbauer spectroscopy and TEM investigation. In all the untreated crystals the mean < M3-O > distance indicates that Me2+(Me = Mn, Fe) prevails at this site (< M3-O > in the range 2.169-2.180 angstrom), in contrast with chemical data obtained by EPMA that yield a simplified formula Ca(REE2/33+square(1/3))Me-3(3+)(SiO4)(Si2O7) O(OH), when normalized to Si = 3.00 apfu. Moreover, when a crystal is heated in air, all geometrical and structural variations indicate the development of an oxidation-dehydrogenation reaction, thus confirming that M3 is occupied by divalent cations before heating. The corresponding dehydrogenation is confirmed by a dramatic lengthening of the donor-acceptor distance. A crystal was annealed under inert atmosphere to verify possible effects of radiation damage on the polyhedral volumes. After prolonged annealing at 700 C, a slight decrease of the unit-cell parameters is observed, suggesting restoring of crystallinity from a "partially metamict" state. Nonetheless, even in the annealed crystal, the < M3-O > distance is still consistent with a dominance of divalent cations at the M3 site. For all the examined crystals, structural data point to an octahedral cation population as follows: M1 = (Me3+, Al); M2 = (Al, Me3+). M3 = (Me2+, Me3+). This assumption is also in agreement with the Mossbauer spectrum, which was fitted to two Lorentzian quadrupole doublets for Fe3+ and one for Fe2+. Values of the isomer shifts (0.36 and 0.37 mm/s for Fe3+; 1.11 mm/s for Fe2+) and the quadrupole splitting (1.96 and 1.02 for Fe3+; 1.90 for Fe2+) show that Fe2+ (similar to 12% of the total iron) is located in M3, while Fe3+ occupies M I and, to lesser extent, M2. TEM-EDS investigations have revealed chemical heterogeneities related to different degree of radiation damage. In particular, areas showing poor crystallinity are relatively enriched in Si and O with respect to the highly crystalline areas, thus suggesting that EPMA chemical data are biased by the presence of metamict areas enriched in SiO2 and likely in H2O. EPMA data were therefore corrected for the excess of silica. The cation population after correction is in keeping with the structural and spectroscopic data. Disregarding minor substitutions, the ideal chemical formula for the epidote-group mineral from Kesebol is CaREEFe3+AlMn2+(Si2O7)(SiO4)O(OH), which is related to ferriallanite-(Ce) by the substitutional vector (M3)(Mn2+) -> M3 (Fe2+).
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| 4. |
- Cámara, Fernando, 1967-, et al.
(författare)
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Old samples - new amphiboles
- 2022
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Ingår i: Abstracts, International Mineralogical Association 23<sup>rd</sup> General meeting. - Lyon. ; , s. 42-42
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The scientific value of old and well-preserved collections is priceless. Samples that already have been studied and described can still give very useful information. For instance, minerals with complex solid solutions like amphiboles sometimes show new compositions that are feasible because of crystal-chemistry and charge arrangements, based on the current classification scheme by Hawthorne et al. (2012) for the amphibole supergroup. In the last four years, a fruitful collaboration between the Swedish Museum of Natural History and the Department of Earth Sciences of the University of Milan has allowed the identification of new amphibole species, recognized by CNMNC-IMA. First of all, we identified hjalmarite, [ANaB(NaMn)CMg5TSi8O22W(OH)2], which is related to richterite via the homovalent substitution [B]Ca2+ → [B]Mn2+, and is the second recognized member of the sodium–(magnesium–iron–manganese) subgroup, after ferri-ghoseite. Sjögren (1891) had described a physically similar, MnO-rich sample from Långban, named “astochit”. A related amphibole, although belonging to a different subgroup, that we have formally described is potassic-richterite, [AKB(NaCa)CMg5TSi8O22W(OH)2]. It was found in a sample from the Pajsberg iron and manganese ore mines, which was originally collected by the mineralogist Lars Johan Igelström, probably in the 1850s. The most recent amphibole we have described is ferri-taramite [ANaB(NaCa)C(Mg3Fe3+2)T(Si6Al2)O22W(OH)2], found in a skarn sample from the Jakobsberg manganese mine: it was once examined by Flink (1914), who noted the unusual character of the amphibole and described it as a “strange hornblende”.
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| 5. |
- Cámara, Fernando, 1967-, et al.
(författare)
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Zinkgruvanite, Ba4Mn2+4Fe3+2(Si2O7)2(SO4)2O2(OH)2, a new ericssonite-group mineral from the Zinkgruvan Zn-Pb-Ag-Cu deposit, Askersund, Örebro County, Sweden.
- 2021
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Ingår i: European journal of mineralogy. - : Nicolaus Copernicus University Press. - 0935-1221 .- 1617-4011. ; 33:6, s. 659-673
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Tidskriftsartikel (refereegranskat)abstract
- Zinkgruvanite, ideally Ba4Mn2+4Fe3+2(Si2O7)2(SO4)2O2(OH)2, is a new member of the ericssonite group, found in Ba-rich drill core samples from a sphalerite+galena- and diopside-rich metatuffite succession from the Zinkgruvan mine, Örebro county, Sweden. Zinkgruvanite is associated with massive baryte, barytocalcite, diopside and minor witherite, cerchiaraite-(Al) and sulfide minerals. It occurs as subhedral to euhedral flattened and elongated crystals up to 4 mm. It is almost black, semi-opaque with a dark brown streak. The luster is vitreous to sub-adamantine on crystal faces, resinous on fractures. The mineral is brittle with an uneven fracture. VHN100 = 539 and HMohs ~4½. In thin fragments, it is reddish-black, translucent and optically biaxial (+), 2Vz > 70°. Pleochroism is strong, deep brown-red (E ⊥ {001} cleavage) to olive-pale brown. Chemical point analyses by WDS-EPMA together with iron valencies determined from Mössbauer spectroscopy, yielded the empirical formula (based on 26 O+OH+F+Cl anions): (Ba4.02Na0.03)Σ4.05(Mn1.79Fe2+1.56Fe3+0.42Mg0.14Ca0.10Ni0.01Zn0.01)Σ4.03 (Fe3+1.74Ti0.20Al0.06)Σ2.00Si4(S1.61Si0.32P0.07)Σ1.99O24(OH1.63Cl0.29F0.08)Σ2.00. The mineral is triclinic, space group P–1, with unit-cell parameters a = 5.3982(1) Å, b = 7.0237(1) Å, c = 14.8108(4) Å, α = 98.256(2)º, β = 93.379(2)º, γ = 89.985(2)º and V = 554.75(2) Å3 for Z = 1. The eight strongest X-ray powder diffraction lines are [d Å (I%; hkl)]: 3.508 (70; 103), 2.980(70; 11–4), 2.814 (68; 1–22), 2.777 (70; 121), 2.699 (714; 200), 2.680 (68; 20–1), 2.125 (100; 124, 204), 2.107 (96; –221). The crystal structure (R1 = 0.0379 for 3204 reflections) is an array of TS (titanium silicate) blocks alternating with intermediate blocks. The TS blocks consist of HOH sheets (H = heteropolyhedral, O = octahedral) parallel to (001). In the O sheet, the Mn2+-dominant MO(1,2,3) sites give ideally Mn2+4 pfu. In the H sheet, the Fe3+-dominant MH sites and AP(1) sites give ideally Fe3+2Ba2 pfu. In the intermediate block, SO4 oxyanions and eleven coordinated Ba atoms give ideally 2 × SO4Ba pfu. Zinkgruvanite is related to ericssonite and ferro-ericssonite in having the same topology and type of linkage of layers in the TS block. Zinkgruvanite is also closely compositionally related to yoshimuraite, Ba4Mn4Ti2(Si2O7)2(PO4)2O2(OH)2, via the coupled heterovalent substitution 2 Ti4+ + 2 (PO4)3- →2 Fe3+ + 2 (SO4)2-, but presents a different type of linkage. The new mineral probably formed during a late stage of regional metamorphism of a Ba-enriched, syngenetic protolith, involving locally generated oxidized fluids of high salinity.
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| 6. |
- Ferrow, Embaie A., et al.
(författare)
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Crystal chemistry and defect structure of ekmanite : New data from transmission electron microscopy and Mossbauer spectroscopy
- 1999
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Ingår i: European Journal of Mineralogy. - 0935-1221. ; 11:2, s. 299-308
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Tidskriftsartikel (refereegranskat)abstract
- Ekmanite is a member of the 2:1 type modulated layer silicates such as ganophyllite and bannisterite. Its chemical composition can be represented by K(M20)[Si32O76](OH)16 (M = Fe2+, Mg2+, Mn2+) where three of eight Si-tetrahedra are inverted across the interlayer sharing an apical oxygen with similarly inverted tetrahedra from the adjacent layers. The arrangement of the regular, D, and inverted, R, tetrahedra has the configuration 4D2R1D1R4D... along the b-axis. In local regions of possibly high Mg/(Mn+Fe) ratio, this configuration is interrupted by the absence of inverted tetrahedra. Ekmanite typically contains a multitude of defects; twinning and both regular and irregular stacking arrangements are the most common ones. Ekmanite is sensitive to oxidation and an unidentified phase, chemically related to it, is always found lining its grain boundaries. This texture results in intergrown rods defining polygons where the central parts do not contain ekmanite. The Mossbauer spectrum consists of Fe2+ and Fe3+ absorption doublets with the Fe2+ absorption composed of two Gaussian line pairs and the Fe3+ absorption of a single but broad line pair.
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| 7. |
- Holtstam, Dan, 1963-, et al.
(författare)
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An 18th century find of an erratic lazulite-andalusite-quartz boulder in Södermanland, Sweden, and its implications
- 2019
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Ingår i: GFF. - Stockholm : Taylor & Francis. - 1103-5897 .- 2000-0863. ; 141:3, s. 216-221
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Tidskriftsartikel (refereegranskat)abstract
- At some point in the 1750s, a jeweller-apprentice by the name Jacob Hässelgren found an erratic bouldernext to the Eskilstuna country road in the neighbourhood of Ärla in Södermanland. It contained a deep bluemass of lazulite, at the time an unknown mineral. Pieces of the find eventually reached Daniel Tilas, TorbernBergman and Axel Fredrik Cronstedt ˗ renowned natural scientists in Sweden ˗ but no detailed studies of thematerial seem to have been carried out by them. Two fragments of the original boulder are still preserved,and a recent examination shows them to consist of mainly lazulite, andalusite, quartz, pyrophyllite, augeliteand svanbergite. The average composition of lazulite is Mg0.700Fe2+0.261Mn0.003Al1.954Fe3+0.017 P2.031O8(OH)2.The mineral assemblage is characteristic of known occurrences of phosphate-Al silicate-quartz appearingalong the Protogine Zone in southern Sweden. Transportation of the boulder from its source rock, likely tobe located somewhere along the Protogine Zone, ought to have occurred in connection with the developmentof the Fennoscandian ice sheet during the final Weichselian deglaciation, and the material waspossibly discharged from floating ice on the Yoldia Sea.
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| 8. |
- Holtstam, Dan, 1963-, et al.
(författare)
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An unusual mineral assemblage of Pb silicates
- 2022
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Ingår i: Geological Society of Sweden, 150 year anniversary meeting, Uppsala, August 17–19 2022, Abstract volume.. - Uppsala. - 9789198783308 ; , s. 356-357
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Konferensbidrag (refereegranskat)abstract
- Rare assemblages of Pb silicates, from skarn in the Långban and Pajsbergs mines, Värmland, Sweden, have been investigated. Minerals observed are alamosite, barysilite, jagoite, joesmithite, melanotekite, nasonite and yangite, together with common metamorphic skarn components like andradite, diopside, hematite and quartz. Jagoite likely formed from primary melanotekite and quartz under the influence of a fluid with high Cl activity. Jagoite is prone to hydrothermal alteration, producing unidentified phases in the system CaO–PbO–SiO2–H2O–(±Cl2).
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| 9. |
- Holtstam, Dan, 1963-, et al.
(författare)
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Arrheniusite-(Ce), CaMg[(Ce7Y3)Ca5](SiO4)3(Si3B3O18)(AsO4)(BO3)F11, a new member of the vicanite group, from the Östanmossa mine, Norberg, Sweden
- 2021
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Ingår i: Canadian Mineralogist. - : Geological and Mineralogical Association of Canada. - 0008-4476 .- 1499-1276. ; 59, s. 177-189
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Tidskriftsartikel (refereegranskat)abstract
- Arrheniusite-(Ce) is a new mineral (IMA 2019-086) from the Östanmossa mine, one of the Bastnäs-type deposits in the Bergslagen ore region, Sweden. It occurs in a metasomatic F-rich skarn, associated with dolomite, tremolite, talc, magnetite, calcite, pyrite, dollaseite-(Ce), parisite-(Ce), bastnäsite-(Ce), fluorbritholite-(Ce) and gadolinite-(Nd). Arrheniusite-(Ce) forms anhedral, greenish-yellow translucent grains, up to 0.8 mm exceptionally. It is optically uniaxial (-), with ω = 1.750(5), ε = 1.725(5), and non-pleochroic in thin section. The calculated density is 4.78(1) g/cm3. Arrheniusite-(Ce) is trigonal, space group R3m, with unit-cell parameters a = 10.8082(3) Å, c = 27.5196(9) Å, and V = 2784.07(14) Å3 for Z = 3. The crystal structure was refined from X-ray diffraction data to R1 = 3.85 for 2286 observed reflections [Fo > 4σ(Fo)]. The empirical formula for the fragment used for the structural study, based on EPMA data and results from the structure refinement, is (Ca0.65As3+0.35)Σ1(Mg0.57Fe2+0.30As5+0.10Al0.03)Σ1[(Ce2.24Nd2.13La0.86Gd0.74Sm0.71Pr0.37)Σ7.05(Y2.76Dy0.26Er0.11Tb0.08Tm0.01Ho0.04Yb0.01)Σ3.27Ca4.14]Σ14.46(SiO4)3[(Si3.26B2.74)Σ6O17.31F0.69][(As5+0.65Si0.22P0.13)Σ1O4](B0.77O3)F11; the ideal formula obtained is CaMg[(Ce7Y3)Ca5](SiO4)3(Si3B3O18)(AsO4)(BO3)F11. Arrheniusite-(Ce) belongs to the vicanite group of minerals, and is distinct from other isostructural members mainly by having a Mg-dominant, octahedrally coordinated site (M6); it can be considered as a Mg-As analog to hundholmenite-(Y). The three-fold coordinated T5 site is partly occupied by B, like in laptevite-(Ce) and vicanite-(Ce). The mineral name honors C.A. Arrhenius (1757–1824), a Swedish officer and chemist, who first discovered gadolinite-(Y), from the famous Ytterby pegmatite quarry.
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| 10. |
- Holtstam, Dan, et al.
(författare)
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Brattforsite, Mn19(AsO3)12Cl2, a new arsenite mineral relatedto magnussonite, from Brattforsgruvan, Nordmark,Värmland, Sweden
- 2021
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Ingår i: Mineralogy and Petrology. - : Springer Science and Business Media LLC. - 0930-0708 .- 1438-1168. ; 115:5, s. 595-609
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Tidskriftsartikel (refereegranskat)abstract
- Brattforsite is an approved mineral (IMA2019-127), with ideal formula Mn19(AsO3)12Cl2. Associated minerals in the type specimen from the Brattfors mine, Nordmark (Värmland, Sweden) include jacobsite, alleghanyite, phlogopite, calcite anddolomite. Brattforsite, forming subhedral, mostly equant crystals up to 0.5 mm across, is orange to reddish-brown with a white streak, and translucent with a resinous to vitreous lustre. The fracture is uneven to subconchoidal, and no cleavage is observed. It is very weakly pleochroic in yellow, optically biaxial (–) with 2V = 44(5)° and has calculated mean refractive index of 1.981. Measured and calculated density values are 4.49(1) and 4.54(1) g·cm−3, respectively. Chemical analyses yields (in wt%): MgO 0.62, CaO 1.26, MnO 48.66, FeO 0.13, As2O3 46.72, Cl 2.61, H2Ocalc 0.07, O ≡ Cl –0.59, sum 99.49, corresponding to the empirical formula (Mn17.67Ca0.58Mg0.40Fe0.05)Σ18.70As12.17O35.90Cl1.90(OH)0.20, based on 38 (O + Cl + OH) atoms per formula unit. The five strongest Bragg peaks in the powder X-ray diffraction pattern are [d (Å), I (%), (hkl)]: 2.843,100, (-444)); 2.828, 99,(444); 1.731, 32, (880); 2.448, 28, (800); 1.739, 25, (088). Brattforsite is monoclinic and pseudotetragonal, space group I2/a, with unit-cell parameters a = 19.5806(7), b = 19.5763(7), c = 19.7595(7) Å, β = 90.393(3)°, V = 7573.9(5) Å3 and Z = 8. The crystal structure was solved and refined to an R1 index of 3.4% for 7445 reflections [Fo > 4σ(Fo)]. Brattforsite has the same overall structural topology as magnussonite (i.e., the species can be considered as homeotypic), but with 12 independent tetrahedrally coordinated As sites and 21 Mn sites with varying (4–8) coordination. The Mn-centered polyhedra, bonded through edge- and face-sharing, give rise to a three-dimensional framework. The (AsO3)3− groups are bonded to this framework through corner- and edge-sharing. Spectroscopic measurements (optical absorption, Raman, FTIR) carried out support the interpretation of the compositional and structural data.
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| 11. |
- Holtstam, Dan, 1963-
(författare)
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Cronstedt 300 år
- 2022
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Ingår i: Geologiskt forum. - : Geologiska Föreningen. - 1104-4721. ; 114, s. 12-16
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- Axel Fredrik Cronstedt (1722-1765) är en av de mest kända svenskarna inom mineralogin. Han beskrev nya grundämnen och mineral samt presenterade ett nydanande klassificeringssystem. Detta byggde på mineralens kemiska sammansättning snarare än deras yttre egenskaper.
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| 12. |
- Holtstam, Dan, 1963-, et al.
(författare)
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Crystal structure and composition of hiärneite, Ca2Zr4Mn3+SbTiO16, and constitution of the calzirtite group
- 2022
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Ingår i: Mineralogical magazine. - : Mineralogical Society. - 0026-461X .- 1471-8022. ; 86:2, s. 314-318
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Tidskriftsartikel (refereegranskat)abstract
- The crystal structure of hiärneite has been refined from single-crystal X-ray diffraction data (λ = 0.71073 Å) on type material from Långban, Värmland, Sweden. The refinement converged to R1 = 0.046 based on 1073 reflections with F2 > 4σ(F2). The tetragonal unit cell, space group I41/acd, has the parameters a = 15.2344(6) Å and c = 10.0891(6) Å with Z = 8. The mineral is isostructural with calzirtite, ideally Ca2Zr5Ti2O16, with a structural topology derived from fluorite. In hiärneite, Mn3+ is ordered at a 4- to 8-fold coordinated site (with a distorted polyhedral coordination figure), without the atom splitting encountered at the corresponding Zr-dominated site of calzirtite. The end-member formula for hiärneite is established as Ca2Zr4Mn3+SbTiO16. The calzirtite group, with calzirtite, hiärneite and tazheranite (cubic ZrO2-x), has been approved by the IMA–CNMNC.
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| 13. |
- Holtstam, Dan, et al.
(författare)
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Delhuyarite-(Ce) – Ce4Mg(Fe3+2W)□(Si2O7)2O6(OH)2 – a new mineral of the chevkinite group, from the Nya Bastnäs Fe–Cu–REE deposit, Sweden
- 2017
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Ingår i: European journal of mineralogy. - : Schweizerbart. - 0935-1221 .- 1617-4011. ; 29:5, s. 897-905
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Tidskriftsartikel (refereegranskat)abstract
- Delhuyarite-(Ce) is a new mineral (IMA no. 2016-091) with ideal formula Ce4Mg(Fe3+2W)□(Si2O7)2O6(OH)2. It is named after Juan and Fausto de Elhuyar (Delhuyar), chemists and metallurgists, who in 1783 isolated tungsten metal for the first time. Associated minerals in the only known sample, from the Nya Bastnäs Fe–Cu–REE deposit (Västmanland, Sweden), include cerite-(Ce), tremolite‒actinolite, percleveite-(Ce), bastnäsite-(Ce), ferriallanite-(Ce), törnebohmite-(Ce), magnetite, chalcopyrite, quartz and scheelite. Delhuyarite-(Ce), which forms subhedral crystals up to 0.3mm long, is brown–black with a dark brown streak and translucent with an adamantine lustre. It is pleochroic in black to rust red and optically biaxial (-). Calculated density and mean refractive index are 5.20 g·cm-3 and 1.94, respectively. Chemical analyses (electron microprobe) gave (in wt%) La2O3 14.58, Ce2O3 23.29, Pr2O3 1.89, Nd2O3 6.13, Sm2O3 0.74, Gd2O3 0.37, Dy2O3 0.03, Er2O3 0.04, Yb2O3 0.12, Y2O3 0.22, CaO 0.76, Fe2O3 12.86, MgO 2.43, Al2O3 0.73, SiO2 18.16, TiO2 0.09, WO3 15.53, H2Ocalc 1.33, F 0.05, Cl 0.03, O=(F, Cl) 0.03, sum 99.35, corresponding to an empirical formula: (Ce1.89La1.19Nd0.48Pr0.15Sm0.06Gd0.03Y0.03Ca0.18)Σ4.01(Fe3+2.14W0.89Mg0.80Al0.19Ti0.02)Σ4.04Si4.01O20(OH1.96F0.04)Σ2, based on 22 O atoms per formula unit (apfu). The presence of H2O is confirmed by IR-spectroscopy, from a strong absorption band at 3495 cm-1. Delhuyarite-(Ce) is monoclinic, space group C2/m, with unit-cell parameters a =13.6020(6)Å, b = 5.7445(3)Å, c = 10.9996(5)Å, β = 100.721(4)°, V = 844.47 (6)Å3 and Z = 2 (data for natural crystal). The crystal structure was refined to an R1 index of 3.9% (natural crystal) and 1.8% (annealed). Delhuyarite-(Ce) has the same structural topology as chevkinite subgroup minerals, e.g. chevkinite-(Ce). It is the only mineral of the group with a significant content of W6+ = 0.89 apfu. In delhuyarite-(Ce), Mg is dominant at the M1 site as in polyakovite-(Ce); the composition of the M2, M3 and M4 sites is [(Fe3+2W)□], with M2 being 50% vacant.
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| 14. |
- Holtstam, Dan, 1963-
(författare)
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Den outsläckliga törsten efter kobolt
- 2019
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Ingår i: Geologiskt forum. - Stockholm. - 1104-4721. ; 2019:103, s. 25-28
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- The shift to electric vehicles and the growing production of rechargeable batteries needed in these have dramatically increased the global demand for cobalt. Most of the metal comes from less stable areas in the world, which makes the supply precarious. The article describes the present situation (in Swedish), and gives a brief overview of the main sources of cobalt in the world today and the prospects for exploiting reserves in Sweden.
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| 15. |
- Holtstam, Dan, 1963-, et al.
(författare)
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Ferri-taramite, a new member of the amphibole supergroup, from the Jakobsberg Mn-Fe deposit, Varmland, Sweden
- 2022
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Ingår i: European Journal of Mineralogy. - : Copernicus GmbH. - 0935-1221 .- 1617-4011. ; 34:5, s. 451-462
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Tidskriftsartikel (refereegranskat)abstract
- Ferri-taramite (IMA CNMNC 2021-046), ideally Na-A(B) (CaNa)(C) (Mg3Fe23+)(Si6Al2)O-22(W) (OH)(2), occurs in skarn from the Jakobsberg manganese mine, Varmland, Sweden. Associated minerals are celsian, phlogopite, aegirine-augite, andradite, hancockite, melanotekite, microcline (var. hyalophane), calcite, baryte, prehnite, macedonite and oxyplumboromeite. Conditions of formation, close to peak metamorphism (at circa 650 degrees C and 0.4 GPa), include silica undersaturation, a slightly peralkaline character and relatively high oxygen fugacities. Ferri-taramite forms poikiloblastic crystals up to 5 mm and is dark brownish black with a yellowish grey streak. The amphibole is brittle with an uneven to splintery fracture. Cleavage parallel to {110} is good. Hardness (Mohs) is similar to 6, and D-calc = 3.227(5) g cm(-3). Holotype ferri-taramite has the experimental unit formula (A)(Na0.79K0.16Pb0.01)(Sigma 0.96)(B) (Ca1.26Na0.72Mn0.022+)(Sigma 2)(C )(Mg2.66Mn0.582+ Fe0.162+Zn0.02Fe1.263+ Al0.26Ti0.06)(Sigma)(T)(5.00) (Al1.86Si6.14)Sigma 8O(22)(W) (OH)(2), based on chemical analyses (EDS, laser-ablation ICP-MS) and spectroscopic (Mossbauer, infrared) and single-crystal X-ray diffraction data. The mineral is optically biaxial (-), with alpha = 1.670(5), beta = 1.680(5) and gamma = 1.685(5) in white light and 2 V-meas = 70(10)degrees and 2 V-calc = 70.2 degrees. Ferri-taramite is distinctly pleochroic in transmitted light, with X pale yellow, Y dark brown, Z yellowish brown and absorption Y> Z> X. The eight strongest reflections in the X-ray powder pattern (d values (in angstrom), I-rel, hkl) are 8.44, 60, 110; 3.392, 25, 131; 3.281, 39, 240; 3.140, 100, 310; 2.816, 45, 330; 2.7104, 38, 151; 1.3654, 26, 461; and 1.4451, 33, (6) over bar 61. Refined unit-cell parameters from single-crystal diffraction data are a = 9.89596(13), b = 18.015(2), c = 5.32164(7) angstrom, beta = 105.003(13)degrees and V = 916.38(2) angstrom(3) for Z = 2. Refinement of the crystal structure yielded R = 2.26 % for 2722 reflections with I-0 >2 sigma (I). The Mn2+ and Fe2+ ions show preference for the M1 and M3 octahedrally coordinated sites, whereas Fe3+ is strongly ordered at M2. The A-group cations, K and Na, are split over two subsites, A (m) and A(2), respectively.
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| 16. |
- Holtstam, Dan, 1963-, et al.
(författare)
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Fluorbritholite-(Nd), Ca2Nd3(SiO4)3F, a new and key mineral for neodymium sequestration in REE skarns
- 2023
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Ingår i: Mineralogical magazine. - 0026-461X .- 1471-8022. ; 87:5, s. 731-737
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Tidskriftsartikel (refereegranskat)abstract
- Fluorbritholite-(Nd), ideally Ca2Nd3(SiO4)3F, 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 (-). Dcalc = 4.92(1) g·cm-3 and ncalc = 1.795. The empirical chemical formula from electron microprobe (WDS) point analyses is (Ca1.62Nd0.97Ce0.83Y0.52Sm0.30Gd0.23Pr0.17La0.16Dy0.11Er0.03Tb0.03Ho0.01Yb0.01)Σ4.99(Si2.92P0.08As0.01)Σ3.01O12.00[O0.48F0.26(OH)0.14Cl0.10Br0.02]Σ1.00. The crystal structure of fluorbritholite-(Nd) was refined from single-crystal X-ray diffraction data to R1= 0.043 for 704 unique reflections. It belongs to the hexagonal system, space group P63/m, with unit cell parameters a = 9.5994(3), c = 6.9892(4) Å, V = 557.76(5) Å3 for Z = 2. Fluorbritholite-(Nd) and other britholite-group minerals are a major sink for neodymium in REE-bearing skarns of Bastnäs type.
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| 17. |
- Holtstam, Dan, 1963-, et al.
(författare)
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Garpenbergite, Mn6□As5+Sb5+O10(OH)2, a new mineral related to manganostibite, from the Garpenberg Zn–Pb–Ag deposit, Sweden
- 2022
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Ingår i: Mineralogical magazine. - : Mineralogical Society. - 0026-461X .- 1471-8022. ; 86:1, s. 1-8
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Tidskriftsartikel (refereegranskat)abstract
- Garpenbergite is a new mineral (IMA2020-099) from the Garpenberg Norra mine, Hedemora, Dalarna, Sweden. It occurs with carlfrancisite and minor stibarsen, paradocrasite and filipstadite in a fractured skarn matrix of granular jacobsite, alleghanyite, kutnohorite and dolomite. Crystals are short-prismatic, up to 1.5 mm in length. They have a blackish to greyish brown colour, and are lustrous semi-opaque, with brown streak. Garpenbergite is brittle, with an uneven to subconchoidal fracture. Cleavage is distinct on {010}. Hardness ≈ 5 (Mohs) and VHN100 = 650(40). Dcalc = 4.47(1) g⋅cm−3 , overall ncalc = 1.85. Maximum specular reflectance values (%) obtained are 9.2 (470 nm), 9.1 (546 nm), 9.0 (589 nm) and 8.9 (650 nm). The empirical chemical formula of garpenbergite, based on electron microprobe data, is (Mn2+3.97Mg1.48Mn3+0.26Zn0.29)Σ6.00(As0.89Fe3+0.04Mn3+0.06Si0.01)Σ1.00(Sb0.98Fe0.02)Σ1.00O10[(OH)1.99Cl0.01]Σ2.00. The five strongest Bragg peaks in the powder X-ray diffraction pattern [d, Å(I, %) (hkl)] are 3.05 (30) (002), 2.665 (100) (161), 2.616 (40) (301), 2.586 (25) (251) and 1.545 (45) (462). The orthorhombic unit-cell dimensions (in Å) are a = 8.6790(9), b = 18.9057(19) and c = 6.1066(6), with V = 1001.99(18) Å3 for Z = 4. The crystal structure was refined from single-crystal X-ray diffraction data in the space-group Ibmm to R1 = 3.7% for 957 reflections. Garpenbergite, ideally Mn6As5+Sb5+O10(OH)2, is isostructural with manganostibite, Mn7AsSbO12, but possesses a cation vacancy (□) at an octahedrally coordinated structural site; the two minerals are thus related by the exchange Mn2+ + 2O2– → □ + 2(OH)– . The presence of hydroxyl groups is supported by vibration bands at 3647 and 3622 cm−1 in the Raman spectrum of garpenbergite, and by bond-valence considerations.
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| 18. |
- Holtstam, Dan, 1963-
(författare)
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Hedins första stuff
- 2023
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Ingår i: Geologiskt forum. - Stockholm : Geologiska Föreningen. - 1104-4721. ; 117, s. 21-21
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Tidskriftsartikel (populärvet., debatt m.m.)
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| 19. |
- Holtstam, Dan, 1963-, et al.
(författare)
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Hjalmarite, a new Na-Mn member of the amphibole supergroup, from Mn skarn in the Långban deposit, Värmland, Sweden.
- 2019
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Ingår i: European journal of mineralogy. - : Schweizerbart. - 0935-1221 .- 1617-4011. ; 31, s. 565-574
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Tidskriftsartikel (refereegranskat)abstract
- Hjalmarite, ideally ANaB(NaMn)CMg5TSi8O22W(OH)2, is a new root-name member of the amphibole supergroup, discovered in skarn from the Långban Fe-Mn-(Ba-As-Pb-Sb-Be-B) deposit, Filipstad, Värmland, Sweden (IMA-CNMNC 2017-070). It occurs closely associated with mainly rhodonite and quartz. It is grayish white with vitreous luster and non-fluorescent. The crystals are up to 5 mm in length and display splintery fracture and perfect cleavage along {110}. Hjalmarite is colorless (non-pleochroic) in thin section and optically biaxial (-), with α = 1.620(5), β = 1.630(5), γ = 1.640(5). The calculated density is 3.12 Mg/m3. Average VHN100 is 782, corresponding to circa 5½ Mohs. An empirical formula, derived from EPMA analyses in combination with crystal structure refinements, is (Na0.84K0.16)Σ1(Na1.01Mn0.55Ca0.43Sr0.01) Σ2(Mg3.83Mn1.16Al0.01) Σ5(Si7.99Al0.01) Σ8O22(OH1.92F0.08)Σ2. An infra-red spectrum of hjalmarite shows distinct absorption bands at 3673 cm-1 and 3731 cm-1 polarized in the α direction. The eight strongest Bragg peaks in the powder X-ray diffraction pattern are [d (Å), I (%), (hkl)]: 3.164, 100, (310); 2.837, 50, (330); 8.50, 44, (110); 3.302; 40, (240); 1.670, 34, (461); 1.448, 32, (-661); 2.727, 30, (151); 2.183, 18 (261).Single-crystal X-ray diffraction data were collected at 298 K and 180 K. The crystal structure was refined in space group C2/m to R1=2.6% [I>2(I)], with observed unit-cell parameters a = 9.9113(3), b = 18.1361(4), c = 5.2831(5) Å, β=103.658(5)° and V = 922.80(9) Å3 at ambient temperature. The A and M(4) sites split into A(m) (K+), A(2) (Na+), and M(4’) (Mn2+) subsites, respectively. Among the octahedrally coordinated C group cations, Mn2+ orders strongly at the M(2) site. No significant violation of C2/m symmetry or change in the structure topology is detected at low temperature (R1=2.1%). The hjalmarite-bearing skarn formed at peak regional metamorphism, T ≥ 600°C, at conditions of high SiO2 activity and relatively low oxygen fugacity. The mineral name honors the Swedish geologist and mineralogist S.A. Hjalmar Sjögren (1856–1922).
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| 20. |
- Holtstam, Dan, 1963-
(författare)
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Hubeit från Harstigen - andra lokalen i världen
- 2020
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Ingår i: Långbansnytt. - 1650-4968. ; 26, s. 13-14
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- Hubeite occurs in an old museum specimen of rhodonite from the Harstigen mine, in a fissure in pyroxene skarn, associated with rhodonite, barite, gonyerite and calcite. Chemical and X-ray crystallographic data are very close to those of the type material from Hubei Province, PR China. A 57Fe Mössbauer spectrum is provided.
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| 21. |
- Holtstam, Dan, 1963-, et al.
(författare)
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Instalment of the margarosanite group, and data on walstromite–margarosanite solid solutions from the Jakobsberg Mn–Fe deposit, Värmland, Sweden
- 2021
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Ingår i: Mineralogical magazine. - : Mineralogical Society. - 0026-461X .- 1471-8022. ; 85, s. 224-232
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Tidskriftsartikel (refereegranskat)abstract
- The margarosanite group (now officially confirmed by IMA-CNMNC) consists of triclinic Ca-(Ba, Pb) cyclosilicates with three-membered [Si3O9]6- rings (3R), with the general formula AB2Si3O9, where A = Pb, Ba, Ca and B = Ca. A closest-packed arrangement of O atoms parallel to (101) hosts Si and B cations in interstitial sites in alternating layers. The 3R layer has three independent Si sites in each ring. Divalent cations occupy three independent sites: Ca in B occupies two nonequivalent sites, Ca1 (8-fold coordinated), and Ca2 (6-fold coordinated). A (=Ca2) is occupied by Pb2+ (or Ba2+) in 6+4 coordination, or 6+1 when occupied by Ca; this third site occurs within the 3R-layer in a peripheral position. Three minerals belong to this group: margarosanite (ideally PbCa2Si3O9), walstromite (BaCa2Si3O9) and breyite (CaCa2Si3O9). So far, no solid solutions involving the Ca1 and Ca2 sites have been described. Therefore, root names depend on the composition of the Ca3 site only. Isomorphic replacement at the Ca3 sites has been noted. We here report data on a skarn sample from the Jakobsberg Mn-Fe oxide deposit, in Värmland (Sweden), representing intermediate compositions on the walstromite-margarosanite binary, in the range ca. 50–70% mol.% BaCa2Si3O9. The plumbian walstromite is closely associated with celsian, phlogopite, andradite, vesuvianite, diopside and nasonite. A crystal-structure refinement (R1 = 4.8%) confirmed the structure type, and showed that the Ca3 (Ba, Pb) site is split into two positions separated by 0.39 Å, with the Ba atoms found slightly more peripheral to the 3R-layers.
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| 22. |
- Holtstam, Dan, 1963-, et al.
(författare)
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Jagoite revisited
- 2022
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Ingår i: Abstracts, International Mineralogical Association, 23<sup>rd</sup> General meeting. - Lyon. ; , s. 34-34
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Jagoite, nominal formula Pb11Fe5Si12O41Cl3, was described in 1957 by Blix et al. It is only known from the Långban and Pajsberg Fe-Mn deposits, in the Filipstad district, Värmland, Sweden. The crystal structure was solved by Mellini & Merlino in 1981. We have reinvestigated the mineral in samples from both localities. The crystal structure was refined (R1 = 1.2% for 2090 reflections with Fo > 4σ(Fo)) from type material and the original structural model is essentially confirmed. Chemical analyses indicate that Al3+ could substitute for Fe3+ in jagoite, up to 2.3 wt. % Al2O3; Mn and Zn is also present in some samples (up to 1.7 wt.% Mn2O3 and 1.2 wt.% ZnO, respectively). Two tetrahedrally coordinated sites have unusually short bonds, which may indicate substitution of Si by a small cation like B3+. Pb and Cl show stable concentration values and jagoite is essentially anhydrous. 57Fe Mössbauer data have been collected from a powder absorber. The hyperfine parameters are consistent with Fe being present only in trivalent form (high spin), and distributed over a relatively regular 6-coordinated site and distorted 4-coordinated sites. Distinct Raman bands appear at 183, 222, 340, 524, 635, 680, 860, 885, 925, 952, 985 and 1050 cm-1. Jagoite occurs in a skarn assemblage with andradite, diopside, hematite, quartz, together with the Pb silicates alamosite, barysilite, jagoite, joesmithite, melanotekite, nasonite and yangite. Jagoite is the mineral most susceptible to hydrothermal alteration in this association, forming new, poorly known phases in the system CaO-PbO-SiO2-H2O-Cl2.
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| 23. |
- Holtstam, Dan, 1963-, et al.
(författare)
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Kesebolite-(Ce), CeCa2Mn(AsO4) SiO3 (3), a New REE-Bearing Arsenosilicate Mineral from the Kesebol Mine, angstrom mal, Vastra Gotaland, Sweden
- 2020
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Ingår i: Minerals. - : MDPI AG. - 2075-163X. ; 10:4
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Tidskriftsartikel (refereegranskat)abstract
- Kesebolite-(Ce), ideal formula CeCa2Mn(AsO4)[SiO3](3), is a new mineral (IMA No. 2019-097) recovered from mine dumps at the Kesebol Mn-(Fe-Cu) deposit in Vastra Gotaland, Sweden. It occurs with rhodonite, baryte, quartz, calcite, talc, andradite, rhodochrosite, K-feldspar, hematite, gasparite-(Ce), chernovite-(Y) and ferriakasakaite-(Ce). It forms mostly euhedral crystals, with lengthwise striation. The mineral is dark grayish-brown to brown, translucent, with light brown streak. It is optically biaxial (+), with weak pleochroism, and n(calc) = 1.74. H = 5-6 and VHN100 = 825. Fair cleavage is observed on {100}. The calculated density is 3.998(5) gcm(-3). Kesebolite-(Ce) is monoclinic, P2(1)/c, with unit-cell parameters from X-ray single-crystal diffraction data: a = 6.7382(3), b = 13.0368(6), c = 12.0958(6) angstrom, beta = 98.578(2)degrees, and V = 1050.66(9) angstrom(3), with Z = 4. Strongest Bragg peaks in the X-ray powder pattern are: [I(%), d(angstrom) (hkl)] 100, 3.114 (20-2); 92, 2.924 (140); 84, 3.138 (041); 72, 2.908 (014); 57, 3.228 (210); 48, 2.856 (042); 48, 3.002 (132). The unique crystal structure was solved and refined to R1 = 4.6%. It consists of 6-periodic single silicate chains along (001); these are interconnected to infinite (010) strings of alternating, corner-sharing MnO6 and AsO4 polyhedra, altogether forming a trellis-like framework parallel to (100).
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| 24. |
- Holtstam, Dan, 1963-, et al.
(författare)
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Langhofite, Pb2(OH)[WO4(OH)], a new mineral from Långban, Sweden.
- 2020
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Ingår i: Mineralogical magazine. - : Mineralogical Society. - 0026-461X .- 1471-8022. ; 84, s. 381-389
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Tidskriftsartikel (refereegranskat)abstract
- Langhofite, ideally Pb2(OH)[WO4(OH)], is a new mineral from the Långban mine, Värmland, Sweden. The mineral and its name were approved by the International Mineralogical Association Commission on New Minerals, Nomenclature and Classification (IMA2019-005). It occurs in a small vug in hematite–pyroxene skarn associated with calcite, baryte, fluorapatite, mimetite and minor sulfide minerals. Langhofite is triclinic, space group P1, and unit-cell parameters a = 6.6154(1) Å, b = 7.0766(1) Å, c = 7.3296(1) Å, α = 118.175(2)°,β = 94.451(1)°, γ = 101.146(1)° and V = 291.06(1) Å3 for Z = 2. The seven strongest Bragg peaks from powder X-ray diffractometry are[dobs, Å (I )(hkl)]: 6.04(24)(010), 3.26(22)(11-2), 3.181(19)(200), 3.079(24)(1-12), 3.016(100)(020), 2.054(20)(3-11) and 2.050(18)(13-2). Langhofite occurs as euhedral crystals up to 4 mm, elongated along the a axis, with lengthwise striation. Mohs hardness is ca. 2½,based on VHN25 data obtained in the range 130–192. The mineral is brittle, with perfect {010} and {100} cleavages. The calculated density based on the ideal formula is 7.95(1) g⋅cm–3. Langhofite is colourless to white (non-pleochroic) and transparent, with a white streakand adamantine lustre. Reflectance curves show normal dispersion, with maximum values 15.7–13.4% within 400–700 nm. Electron microprobe analyses yield only the metals Pb and W above the detection level. The presence of OH-groups is demonstrated with vibration spectroscopy, from band maxima present at ∼3470 and 3330 cm–1. A distinct Raman peak at ca. 862 cm–1 is related to symmetricW–oxygen stretching vibrations. The crystal structure is novel and was refined to R = 1.6%. It contains [W2O8(OH)2]6– edge-sharingdimers (with highly distorted WO6-octahedra) forming chains along [101] with [(OH)2Pb4]6+ dimers formed by (OH)Pb3 triangles. Chains configure (010) layers linked along [010] by long and weak Pb–O bonds, thus explaining the observed perfect cleavage on{010}. The mineral is named for curator Jörgen Langhof (b. 1965), who collected the discovery sample.
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| 25. |
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