| Reference Type | Journal (article/letter/editorial) |
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| Title | The sulfite anion in ettringite-group minerals: a new mineral species hielscherite, Ca3Si(OH)6(SO4)(SO3)·11H2O, and the thaumasite–hielscherite solid-solution series |
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| Journal | Mineralogical Magazine |
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| Authors | Pekov, I. V. | Author |
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| Chukanov, N. V. | Author |
| Britvin, S. N. | Author |
| Kabalov, Y. K. | Author |
| Göttlicher, J. | Author |
| Yapaskurt, V. O. | Author |
| Zadov, A. E. | Author |
| Krivovichev, S. V. | Author |
| Schüller, W. | Author |
| Ternes, B. | Author |
| Year | 2012 (October) | Volume | 76 |
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| Issue | 5 |
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| Publisher | Mineralogical Society |
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| Download URL | https://rruff.info/rruff_1.0/uploads/MM76_1133.pdf+ |
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| DOI | doi:10.1180/minmag.2012.076.5.06Search in ResearchGate |
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| Generate Citation Formats |
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| Classification | Not set | LoC | Not set |
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| Mindat Ref. ID | 244277 | Long-form Identifier | mindat:1:5:244277:2 |
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| GUID | 0 |
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| Full Reference | Pekov, I. V., Chukanov, N. V., Britvin, S. N., Kabalov, Y. K., Göttlicher, J., Yapaskurt, V. O., Zadov, A. E., Krivovichev, S. V., Schüller, W., Ternes, B. (2012) The sulfite anion in ettringite-group minerals: a new mineral species hielscherite, Ca3Si(OH)6(SO4)(SO3)·11H2O, and the thaumasite–hielscherite solid-solution series. Mineralogical Magazine, 76 (5) 1133-1152 doi:10.1180/minmag.2012.076.5.06 |
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| Plain Text | Pekov, I. V., Chukanov, N. V., Britvin, S. N., Kabalov, Y. K., Göttlicher, J., Yapaskurt, V. O., Zadov, A. E., Krivovichev, S. V., Schüller, W., Ternes, B. (2012) The sulfite anion in ettringite-group minerals: a new mineral species hielscherite, Ca3Si(OH)6(SO4)(SO3)·11H2O, and the thaumasite–hielscherite solid-solution series. Mineralogical Magazine, 76 (5) 1133-1152 doi:10.1180/minmag.2012.076.5.06 |
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| Abstract/Notes | Hielscherite, ideally Ca3Si(OH)6(SO4)(SO3)·11H2O, (IMA 2011-037) is the first ettringite-group mineral with essential sulfite. We have identified a continuous natural solid-solution series from endmember thaumasite, Ca3Si(OH)6(SO4)(CO3)·12H2O, to a composition with at least 77 mol.% endmember hielscherite. In this series, the SO3:CO3 ratio is variable, whereas the SO4 content remains constant. Compositions with more than 50 mol.% endmember hielscherite have only been found at Graulay quarry near Hillesheim in the western Eifel Mountains, Rhineland-Palatinate, where they occur with phillipsite-K, chabazite-Ca and gypsum in cavities in alkaline basalt. Sulfite-rich thaumasite has been found in hydrothermal assemblages in young alkaline basalts in two volcanic regions of Germany: it is widespread at Graulay quarry and occurs at Rother Kopf, Schellkopf and Bellerberg quarries in Eifel district; it has also been found at Zeilberg quarry, Franconia, Bavaria. Hielscherite forms matted fibrous aggregates up to 1 cm across and groups of acicular to prismatic hexagonal crystals up to 0.3 × 0.3 × 1.5 mm. Individual crystals are colourless and transparent with a vitreous lustre and crystal aggregates are white with a silky lustre. The Mohs hardness is 2–2½. Measured and calculated densities are Dmeas = 1.82(3) and Dcalc = 1.79 g cm–3. Hielscherite is optically uniaxial (–), ω = 1.494(2), ε = 1.476(2). The mean chemical composition of holotype material (determined by electron microprobe for Ca, Al, Si, and S and gas chromatography for C, H and N, with the S4+:S6+ ratio from the crystal-structure data) is CaO 27.15, Al2O3 2.33, SiO2 7.04, CO2 2.71, SO2 6.40, SO3 12.91, N2O5 0.42, H2O 39.22, total 98.18 wt.%. The empirical formula on the basis of 3 Ca atoms per formula unit is Ca3(Si0.73Al0.28)Σ1.01(OH)5.71(SO4)1.00(SO3)0.62(CO3)0.38(NO3)0.05·10.63H2O. The presence of sulfite was confirmed by crystal-structure analysis and infrared and X-ray absorption near edge structure spectra. The crystal structure of sulfite-rich thaumasite from Zeilberg quarry was solved by direct methods based on single-crystal X-ray diffraction data (R1 = 0.064). The structure of hielscherite was refined using the Rietveld method (Rwp = 0.0317). Hielscherite is hexagonal, P63, a = 11.1178(2), c = 10.5381(2) Å, V = 1128.06(4) Å3 and Z = 2. The strongest reflections in the X-ray powder pattern [(d, Å (I)(hkl)] are: 9.62(100)(010,100); 5.551(50)(110); 4.616(37)(012,102); 3.823(64)(112); 3.436(25)(211), 2.742(38)(032,302), 2.528(37)(123,213), 2.180(35)(042,402;223). In both hielscherite and sulfite-rich thaumasite, pyramidal sulfite groups occupy the same site as trigonal carbonate groups, with analogous O sites, whereas tetrahedral sulfate groups occupy separate positions. Hielscherite is named in honour of the German mineral collector Klaus Hielscher (b. 1957). |
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