Jakobssonite, CaAlF 5 , a new mineral from fumaroles at the Eldfell and Hekla volcanoes, Iceland
The new mineral jakobssonite, ideally CaAlF5, was first found in crusts collected in 1988 from a fumarole on the Eldfell volcano, Heimaey Island, Iceland. It was subsequently found in similar crusts collected in 1991 from a fumarole on the Hekla volcano, Iceland. It is associated with leonardsenite...
Published in: | Mineralogical Magazine |
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2012
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Online Access: | https://curis.ku.dk/portal/da/publications/jakobssonite-caalf5-a-new-mineral-from-fumaroles-at-the-eldfell-and-hekla-volcanoes-iceland(9e05f04f-6eee-4ca4-b95f-63d91b19a600).html https://doi.org/10.1180/minmag.2012.076.3.22 |
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ftcopenhagenunip:oai:pure.atira.dk:publications/9e05f04f-6eee-4ca4-b95f-63d91b19a600 2023-12-17T10:31:18+01:00 Jakobssonite, CaAlF 5 , a new mineral from fumaroles at the Eldfell and Hekla volcanoes, Iceland Balic Zunic, Tonci Garavelli, A. Mitolo, D. Acquafredda, P. Leonardsen, E. 2012 https://curis.ku.dk/portal/da/publications/jakobssonite-caalf5-a-new-mineral-from-fumaroles-at-the-eldfell-and-hekla-volcanoes-iceland(9e05f04f-6eee-4ca4-b95f-63d91b19a600).html https://doi.org/10.1180/minmag.2012.076.3.22 eng eng info:eu-repo/semantics/closedAccess Balic Zunic , T , Garavelli , A , Mitolo , D , Acquafredda , P & Leonardsen , E 2012 , ' Jakobssonite, CaAlF 5 , a new mineral from fumaroles at the Eldfell and Hekla volcanoes, Iceland ' , Mineralogical Magazine , vol. 76 , no. 3 , pp. 751–760 . https://doi.org/10.1180/minmag.2012.076.3.22 article 2012 ftcopenhagenunip https://doi.org/10.1180/minmag.2012.076.3.22 2023-11-22T23:59:32Z The new mineral jakobssonite, ideally CaAlF5, was first found in crusts collected in 1988 from a fumarole on the Eldfell volcano, Heimaey Island, Iceland. It was subsequently found in similar crusts collected in 1991 from a fumarole on the Hekla volcano, Iceland. It is associated with leonardsenite (IMA2011-059), ralstonite, heklaite, anhydrite, gypsum, jarosite, hematite, opal and several fluoride minerals that have not been fully characterized. Jakobssonite occurs as soft white fragile crusts of acicular crystals <50 mm long. Its calculated density is 2.89 g cm3. Chemical analyses by energy dispersive spectrometry on a scanning electron microscope produced a mean elemental composition as follows: Ca, 18.99; Al, 18.55; Mg, 1.33; Na, 0.33; F, 50.20; O, 10.39; total 99.79 wt.%. The empirical chemical formula, calculated on the basis of 7 atoms per formula unit with all of the oxygen as OH, is (Ca0.73Mg0.09Na0.02)S0.84Al1.06F4.09(OH)1.01. Jakobssonite is monoclinic, space group C2/c, with a = 8.601(1), b = 6.2903(6), c = 7.2190(7) Å , b = 114.61(1)o, V = 355.09(8) Å3 and Z = 4. The crystal structure contains chains of [AlF6] octahedra which run parallel to the c axis. These chains are interconnected by chains of [CaF7] pentagonal bipyramids. Jakobssonite is isostructural with several other CaMIIIF5 compounds. The eight strongest lines in the powder diffraction diagram [d in Å (I) (hkl)] are as follows: 4.91 (18) (110), 3.92 (76) (200), 3.15 (68) (020), 3.13 (100) (1-1-2 ), 2.27 (22) (2-2-2 ), 1.957 (21) (400), 1.814 (20) (1-3-2), 1.805 (22) (20-4 ). The chemical and crystal-structure analyses of jakobssonite are similar to synthetic CaAlF5 with minor substitutions of light elements (e.g. Na) or vacancies for Ca, and OH for F. Article in Journal/Newspaper Heimaey Hekla Iceland University of Copenhagen: Research Eldfell ENVELOPE(-20.250,-20.250,63.433,63.433) Heimaey ENVELOPE(-22.486,-22.486,65.099,65.099) Mineralogical Magazine 76 3 751 760 |
institution |
Open Polar |
collection |
University of Copenhagen: Research |
op_collection_id |
ftcopenhagenunip |
language |
English |
description |
The new mineral jakobssonite, ideally CaAlF5, was first found in crusts collected in 1988 from a fumarole on the Eldfell volcano, Heimaey Island, Iceland. It was subsequently found in similar crusts collected in 1991 from a fumarole on the Hekla volcano, Iceland. It is associated with leonardsenite (IMA2011-059), ralstonite, heklaite, anhydrite, gypsum, jarosite, hematite, opal and several fluoride minerals that have not been fully characterized. Jakobssonite occurs as soft white fragile crusts of acicular crystals <50 mm long. Its calculated density is 2.89 g cm3. Chemical analyses by energy dispersive spectrometry on a scanning electron microscope produced a mean elemental composition as follows: Ca, 18.99; Al, 18.55; Mg, 1.33; Na, 0.33; F, 50.20; O, 10.39; total 99.79 wt.%. The empirical chemical formula, calculated on the basis of 7 atoms per formula unit with all of the oxygen as OH, is (Ca0.73Mg0.09Na0.02)S0.84Al1.06F4.09(OH)1.01. Jakobssonite is monoclinic, space group C2/c, with a = 8.601(1), b = 6.2903(6), c = 7.2190(7) Å , b = 114.61(1)o, V = 355.09(8) Å3 and Z = 4. The crystal structure contains chains of [AlF6] octahedra which run parallel to the c axis. These chains are interconnected by chains of [CaF7] pentagonal bipyramids. Jakobssonite is isostructural with several other CaMIIIF5 compounds. The eight strongest lines in the powder diffraction diagram [d in Å (I) (hkl)] are as follows: 4.91 (18) (110), 3.92 (76) (200), 3.15 (68) (020), 3.13 (100) (1-1-2 ), 2.27 (22) (2-2-2 ), 1.957 (21) (400), 1.814 (20) (1-3-2), 1.805 (22) (20-4 ). The chemical and crystal-structure analyses of jakobssonite are similar to synthetic CaAlF5 with minor substitutions of light elements (e.g. Na) or vacancies for Ca, and OH for F. |
format |
Article in Journal/Newspaper |
author |
Balic Zunic, Tonci Garavelli, A. Mitolo, D. Acquafredda, P. Leonardsen, E. |
spellingShingle |
Balic Zunic, Tonci Garavelli, A. Mitolo, D. Acquafredda, P. Leonardsen, E. Jakobssonite, CaAlF 5 , a new mineral from fumaroles at the Eldfell and Hekla volcanoes, Iceland |
author_facet |
Balic Zunic, Tonci Garavelli, A. Mitolo, D. Acquafredda, P. Leonardsen, E. |
author_sort |
Balic Zunic, Tonci |
title |
Jakobssonite, CaAlF 5 , a new mineral from fumaroles at the Eldfell and Hekla volcanoes, Iceland |
title_short |
Jakobssonite, CaAlF 5 , a new mineral from fumaroles at the Eldfell and Hekla volcanoes, Iceland |
title_full |
Jakobssonite, CaAlF 5 , a new mineral from fumaroles at the Eldfell and Hekla volcanoes, Iceland |
title_fullStr |
Jakobssonite, CaAlF 5 , a new mineral from fumaroles at the Eldfell and Hekla volcanoes, Iceland |
title_full_unstemmed |
Jakobssonite, CaAlF 5 , a new mineral from fumaroles at the Eldfell and Hekla volcanoes, Iceland |
title_sort |
jakobssonite, caalf 5 , a new mineral from fumaroles at the eldfell and hekla volcanoes, iceland |
publishDate |
2012 |
url |
https://curis.ku.dk/portal/da/publications/jakobssonite-caalf5-a-new-mineral-from-fumaroles-at-the-eldfell-and-hekla-volcanoes-iceland(9e05f04f-6eee-4ca4-b95f-63d91b19a600).html https://doi.org/10.1180/minmag.2012.076.3.22 |
long_lat |
ENVELOPE(-20.250,-20.250,63.433,63.433) ENVELOPE(-22.486,-22.486,65.099,65.099) |
geographic |
Eldfell Heimaey |
geographic_facet |
Eldfell Heimaey |
genre |
Heimaey Hekla Iceland |
genre_facet |
Heimaey Hekla Iceland |
op_source |
Balic Zunic , T , Garavelli , A , Mitolo , D , Acquafredda , P & Leonardsen , E 2012 , ' Jakobssonite, CaAlF 5 , a new mineral from fumaroles at the Eldfell and Hekla volcanoes, Iceland ' , Mineralogical Magazine , vol. 76 , no. 3 , pp. 751–760 . https://doi.org/10.1180/minmag.2012.076.3.22 |
op_rights |
info:eu-repo/semantics/closedAccess |
op_doi |
https://doi.org/10.1180/minmag.2012.076.3.22 |
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Mineralogical Magazine |
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76 |
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3 |
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751 |
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