Topsøeite

FeF3(H2O)3
IMA status
  • Approved
IMA symbol
Top
Discovered
1991
IMA approved
2016
Also known as
  • IMA2016-113
  • Topsøeiet
  • UM2008-30-F:FeHO

Where it forms, where it's found

Type locality
Hekla
  1. Rangárþing ytra
  2. Southern Region
  3. Iceland

63.9926°, -19.6658°

1recorded occurrences
Source · OpenStreetMap

Physical

Colour
Yellow
Density
2.330 g/cm³

Crystallography

Crystal system
Tetragonal
Space group
P4/n
Cell parameters
a = 7.8384(4) Å · c = 3.8718(2) Å
Unit cell volume
237.6 ų
Type-locality form

Square-prismatic crystals to 20 µm forming occasional stepped aggregates. Massive veins to 100 µm wide.

Chemical composition

Constituent elements
Mass composition breakdown
ElementAtoms At. mass g/mol Mass g/molMass share
9FFluorineFluorine318.99856.994
34.15%
26FeIronIron155.84555.845
33.46%
8OOxygenOxygen315.99947.997
28.76%
1HHydrogenHydrogen61.0086.048
3.63%
Total166.884100.00%

Mass share = atoms × atomic mass ÷ molar mass × 100

From IMA formula

Synonyms

  • IMA2016-113
  • Topsøeiet
  • UM2008-30-F:FeHO

In other languages

German
IMA 2016-113 · Topsøeit

Classification

Strunz
10th ed.

3.CD.05

  • 3HalidesClass
  • 3.CComplex halidesDivision
  • 3.CDIno-aluminofluoridesGroup
  • 3.CD.05TopsøeiteSpecies

Group, growth & confusion

Commonly confused with
1 mineral

Literature, links & citation

Citations
  1. 2017Hålenius, U., Hatert, F., Pasero, M., Mills, S. J. (2017) New minerals and nomenclature modifications approved in 2017. CNMNC Newsletter No 36. Mineralogical Magazine, 81 (2) 403-409 doi:10.1180/minmag.2017.081.022DOI: 10.1180/minmag.2017.081.022
  2. 2018Balić-Žunić, Tonči, Garavelli, Anna, Mitolo, Donatella (2018) Topsøeite, FeF3(H2O)3, a new fumarolic mineral from the Hekla Volcano, Iceland. European Journal of Mineralogy, 30 (4) 841-848 doi:10.1127/ejm/2018/0030-2751 DOI: 10.1127/ejm/2018/0030-2751
  3. 2020(2020) Topsøeite. Handbook of Mineralogy. Mineralogical Society of America
Cite this entry
@misc{mineral2026,
  author    = {Mineral Index editorial board},
  title     = {Topsøeite — Mineral Index},
  year      = {2026},
  url       = {https://mineralindex.org/minerals/tops-eite-51561},
  note      = {Accessed 2026-05-11}
}