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.

Co-Type Localities:

ⓘ Hekla, Rangárþing ytra, Southern Region, Iceland
ⓘ Eldfell, Heimaey island, Vestmannaeyjar archipelago (Westman islands), Vestmannaeyjar, Southern Region, Iceland

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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Unique IdentifiersHide

Mindat ID:

42796

Long-form identifier:

mindat:1:1:42796:6

GUID
(UUID V4):

800d5b75-cb5c-442e-8394-8440c72f3245

IMA Classification of JakobssoniteHide

IMA status:

Approved

Approval year:

2011

First published:

2012

Type description reference:

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 (3) 751-760 doi:10.1180/minmag.2012.076.3.22

Classification of JakobssoniteHide

Strunz-mindat (2024):

3.CD.15

3 : HALIDES
C : Complex halides
D : Ino-aluminofluorides

Mineral SymbolsHide

As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.

Symbol	Source	Reference
Jak	IMA–CNMNC	Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43

Physical Properties of JakobssoniteHide

Lustre:

Earthy

Transparency:

Transparent

Colour:

White

Streak:

White

Density:

2.89 g/cm³ (Calculated)

Chemistry of JakobssoniteHide

Mindat Formula:

CaAlF₅

Elements listed:

Al, Ca, F - search for minerals with similar chemistry

Crystallography of JakobssoniteHide

Crystal System:

Monoclinic

Class (H-M):

2/m - Prismatic

Space Group:

B2/b

Setting:

C2/c

Cell Parameters:

a = 8.601(1) Å, b = 6.2903(6) Å, c = 7.2190(7) Å
β = 114.61(1)°

Ratio:

a:b:c = 1.367 : 1 : 1.148

Unit Cell V:

355.09 Å³

Morphology:

Acicular crystals which are probably elongated along [100]; fragile crusts.

Crystal StructureHide

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Data courtesy of the American Mineralogist Crystal Structure Database. Click on an AMCSD ID to view structure

ID	Species	Reference	Link	Year	Locality	Pressure (GPa)	Temp (K)
0010259	Jakobssonite	Hemon A, Courbion G (1991) Refinement of the room-temperature structure of alpha-CaAlF5 _cod_database_code 1000300 Acta Crystallographica C47 1302-1303		1991		0	293
0019194	Jakobssonite	Balic-Zunic 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		2012	Hekla volcano, Iceland	0	293

CIF Raw Data - click here to close

data_global
_chemical_name_mineral 'Jakobssonite'
loop_
_publ_author_name
'Hemon A'
'Courbion G'
_journal_name_full 'Acta Crystallographica, Section C'
_journal_volume 47 
_journal_year 1991
_journal_page_first 1302
_journal_page_last 1303
_publ_section_title
;
 Refinement of the room-temperature structure of alpha-CaAlF5
 _cod_database_code 1000300
;
_database_code_amcsd 0010259
_chemical_formula_sum 'Ca Al F5'
_cell_length_a 8.712
_cell_length_b 6.317
_cell_length_c 7.349
_cell_angle_alpha 90
_cell_angle_beta 115.04
_cell_angle_gamma 90
_cell_volume 366.430
_exptl_crystal_density_diffrn      2.937
_symmetry_space_group_name_H-M 'C 1 2/c 1'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  '1/2+x,1/2+y,z'
  'x,-y,1/2+z'
  '1/2+x,1/2-y,1/2+z'
  '-x,y,1/2-z'
  '1/2-x,1/2+y,1/2-z'
  '-x,-y,-z'
  '1/2-x,1/2-y,-z'
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
Ca   0.00000   0.54240   0.25000
Al   0.00000   0.00000   0.00000
F1   0.00000   0.94220   0.25000
F2   0.01140   0.71690   0.97370
F3   0.77890   0.98220   0.88700
loop_
_atom_site_aniso_label
_atom_site_aniso_U_11
_atom_site_aniso_U_22
_atom_site_aniso_U_33
_atom_site_aniso_U_12
_atom_site_aniso_U_13
_atom_site_aniso_U_23
Ca 0.00740 0.00770 0.00680 0.00000 0.00310 0.00000
Al 0.00680 0.00590 0.00580 -0.00020 0.00290 0.00010
F1 0.02070 0.01100 0.00850 0.00000 0.00890 0.00000
F2 0.02230 0.00660 0.01140 0.00060 0.00980 -0.00060
F3 0.00700 0.02430 0.01910 -0.00110 0.00290 0.00000

X-Ray Powder DiffractionHide

Powder Diffraction Data:

d-spacing	Intensity
4.91 Å	(18)
3.92 Å	(76)
3.15 Å	(68)
3.13 Å	(100)
2.270 Å	(22)
1.957 Å	(21)
1.814 Å	(20)
1.805 Å	(22)

Comments:

Sample from Hekla volcano, Iceland.

Geological EnvironmentHide

Paragenetic Mode(s):

Paragenetic Mode	Earliest Age (Ga)
Stage 7: Great Oxidation Event	<2.4
45b : [Other oxidized fumarolic minerals]

Type Occurrence of JakobssoniteHide

Co-Type Localities:

ⓘ Hekla, Rangárþing ytra, Southern Region, Iceland
ⓘ Eldfell, Heimaey island, Vestmannaeyjar archipelago (Westman islands), Vestmannaeyjar, Southern Region, Iceland

General Appearance of Type Material:

Acicular crystals up to 50 µm long. Also as a white overgrowth on a yellowish base of massive ralstonite, anhydrite and jarosite which together form a 2-3 cm thick crust on altered scoria.

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).

Geological Setting of Type Material:

Fumarole at ~230ºC.

Associated Minerals at Type Locality:

Opal	Malladrite	Leonardsenite	Jarosite	Hydrokenoralstonite
Hieratite	Hematite	Heklaite	Gypsum	Fluorite
Chiolite	Anhydrite

Reference:

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.

Synonyms of JakobssoniteHide

IMA2011-036

UM2010-01-F:AlCa

Unnamed (Ca-Al Fluoride)

Common AssociatesHide

Associated Minerals Based on Photo Data:

1 photo of Jakobssonite associated with Verneite

Na₂Ca₃Al₂F₁₄

Related Minerals - Strunz-mindat Grouping Hide

3.CD.05	Rosenbergite	AlF[F_0.5(H₂O)_0.5]₄ · H₂O	Tet. 4/m : P4/n
3.CD.05	Topsøeite	FeF[F_0.5(H₂O)_0.5]₄ · H₂O	Tet. 4/m : P4/n
3.CD.10	Prosopite	CaAl₂F₄[(OH)_4-xF_x]	Mon. 2/m : B2/b

Fluorescence of JakobssoniteHide

In UV light:

Does not fluoresce in LW UV

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.

Internet Links for JakobssoniteHide

mindat.org URL:

https://www.mindat.org/min-42796.html
Please feel free to link to this page.

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External Links:

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Raman and XRD data at RRUFF project

References and PDF downloads at RRUFF project

American Mineralogist Crystal Structure Database

Handbook of Mineralogy page PDF

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References for JakobssoniteHide

Reference List:

Hemon, A., Courbion, G. (1991) Refinement of a room-temperature structure of α-CaAlF5. Acta Crystallographica Section C Crystal Structure Communications, 47 (6) 1302-1303 doi:10.1107/s0108270190013956

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:. p.1-65.

Williams, P. A., Hatert, F., Pasero, M., Mills, S. J. (2011) New minerals and nomenclature modifications approved in 2011, CNMNC Newsletter No. 10. Mineralogical Magazine, 75 (5) 2549-2561 doi:10.1180/minmag.2011.075.5.2549

(2023) Jakobssonite. Handbook of Mineralogy. Mineralogical Society of America

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 references and 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 (e.g. from pseudomorphs).

All localities listed without proper references should be considered as questionable.


Iceland
Southern Peninsula Grindavíkurbær Grindavik ⓘ Fagradalsfjall volcano	Günter Frenz collection +1 other reference
Southern Region Rangárþing eystra ⓘ Fimmvörðuháls eruption site	Balić-Žunić et al. (2016)
Rangárþing ytra ⓘ Hekla (TL)	Williams et al. (2011) +1 other reference
Vestmannaeyjar Vestmannaeyjar archipelago (Westman islands) Heimaey island ⓘ Eldfell (TL)	Williams et al. (2011) +2 other references

Russia
Kamchatka Krai Milkovsky District Tolbachik Volcanic field Great Fissure eruption (Main Fracture) Northern Breakthrough (North Breach) First scoria cone ⓘ Northern fumarole field	Pekov et al. (2015)

Jakobssonite