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Sveinn P. Jakobsson
Specific Gravity:
2.89 (Calculated)
Crystal System:
The name honours Sveinn Peter Jakobsson (20 July 1939, Reykjavík, Iceland - 12 July 2016, Iceland), volcanologist at the Icelandic Institute of Natural History, who was the first person to recognize it.
It is known as a synthetic phase (Hemon & Courbion, 1991). Jakobsson et al. (2008) referred to it as "mineral HA". In the IMA list of unnamed minerals it is listed in the invalid minerals under the code UM2008-//-?[5].

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Classification of JakobssoniteHide

Approval Year:

Physical Properties of JakobssoniteHide

2.89 g/cm3 (Calculated)

Chemical Properties of JakobssoniteHide


Crystallography of JakobssoniteHide

Crystal System:
Class (H-M):
2/m - Prismatic
Space Group:
Cell Parameters:
a = 8.601(1) Å, b = 6.2903(6) Å, c = 7.2190(7) Å
β = 114.61(1)°
a:b:c = 1.367 : 1 : 1.148
Unit Cell V:
355.09 ų
Acicular crystals which are probably elongated along [100]; fragile crusts.

X-Ray Powder DiffractionHide

Powder Diffraction Data:
4.91 (18)
3.92 (76)
3.15 (68)
3.13 (100)
2.270 (22)
1.957 (21)
1.814 (20)
1.805 (22)
Sample from Hekla volcano, Iceland.

Type Occurrence of JakobssoniteHide

Place of Conservation of Type Material:
Type material is deposited in the collections of the Icelandic Institute of Natural History, Reykjavık, Iceland, sample number NI 12256
(Eldfell). A cotype sample has the number NI 15511(Hekla)

Synonyms of JakobssoniteHide

Common AssociatesHide

Hydrokenoralstonite Na0.5(Al,Mg)2(F,OH)6•H2O

Other InformationHide

Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

References for JakobssoniteHide

Reference List:
Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
Hemon, A., Courbion, G. (1991) Refinement of a room-temperature structure of α-CaAlF5. Acta Crystallographica: C47: 1302-1303.
Jakobsson, S.P., Leonardsen, E.S., Balić-Žunić, T., Jonsson, S.S. (2008) Encrustations from three recent volcanic eruptions in Iceland: the 1963-1967 Surtsey, the 1973 Eldfell and the 1991 Hekla eruptions. Fjölrit Náttúrufraedistofnunar: 52: 65 pp.
Balić-Žunić, T., Garavelli, A., Mitolo, D., Acquafredda, P., Leonardsen, E. (2012) Jakobssonite, CaAlF5, a new mineral from fumaroles at the Eldfell and Hekla volcanoes, Iceland. Mineralogical Magazine: 76: 751-760.

Internet Links for JakobssoniteHide

Localities for JakobssoniteHide

This map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.

Locality ListHide

- This locality has map coordinates listed. - This locality has estimated coordinates. ⓘ - Click for further information on this occurrence. ? - Indicates mineral may be doubtful at this locality. - Good crystals or important locality for species. - World class for species or very significant. (TL) - Type Locality for a valid mineral species. (FRL) - First Recorded Locality for everything else (eg varieties). Struck out - Mineral was erroneously reported from this locality. Faded * - Never found at this locality but inferred to have existed at some point in the past (eg from pseudomorphs.)

All localities listed without proper references should be considered as questionable.
Iceland (TL)
  • Southern Region
Balić-Žunić, T., Garavelli, A., Mitolo, D., Acquafredda, P. & Leonardsen, E. (2012): Jakobssonite, CaAlF5, a new mineral from fumaroles at the Eldfell and Hekla volcanoes, Iceland. Mineralogical Magazine, 76, 751-760.
    • Vestmannaeyjar archipelago (Westman islands)
      • Heimaey island
Balić-Žunić, T., Garavelli, A., Mitolo, D., Acquafredda, P. & Leonardsen, E. (2012): Jakobssonite, CaAlF5, a new mineral from fumaroles at the Eldfell and Hekla volcanoes, Iceland. Mineralogical Magazine, 76, 751-760.
  • Kamchatka Krai
    • Tolbachik volcano
      • Great Fissure eruption (Main Fracture)
        • Northern Breakthrough (North Breach)
          • First scoria cone (First cinder cone)
Pekov, I. V., Zubkova, N. V., Britvin, S. N., Yapaskurt, V. O., Chukanov, N. V., Lykova, I. S., ... & Pushcharovsky, D. Y. (2015). New zinc and potassium chlorides from fumaroles of the Tolbachik volcano, Kamchatka, Russia: mineral data and crystal chemistry. III. Cryobostryxite, KZnCl3· 2H2O. European Journal of Mineralogy, 27(6), 805-812
Mineral and/or Locality  
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