Thermessaite-(NH4)

(NH4)2AlF3(SO4)
IMA status
  • Approved
IMA symbol
Tms-NH4
IMA approved
2011
Also known as
  • IMA2011-077
  • Thermessaiet-(NH4)
  • Unnamed (NH4-analogue of Thermessaite)

Where it forms, where it's found

Geological setting

On the surface of pyroclastic breccia.

Type locality
La Fossa crater
  1. Vulcano Island
  2. Lipari
  3. Eolie Islands (Aeolian Islands)
  4. Metropolitan City of Messina
  5. Sicily
  6. Italy

38.4034°, 14.9614°

3recorded occurrences
Source · OpenStreetMap

Physical

Transparency
Transparent
Colour
Colourless to white
Streak
White
Density
2.815 g/cm³

Optical

UV response
no

Crystallography

Crystal system
Orthorhombic
Space group
#63
Cell parameters
a = 11.3005(3) Å · b = 8.6125(3) Å · c = 6.8501(2) Å
Ratio a:b:c
1 : 0.762 : 0.606
Morphology

Acicular.

Type-locality form

Micrometer-sized, sharp, prismatic crystals, forming aggregates.

Comment

Cell of anthropogenic material: a = 11.286(2), 8.607(2), 6.843(1) A.

Chemical composition

Constituent elements
Mass composition breakdown
ElementAtoms At. mass g/mol Mass g/molMass share
8OOxygenOxygen415.99963.996
29.61%
9FFluorineFluorine318.99856.994
26.37%
16SSulfurSulfur132.06032.060
14.84%
7NNitrogenNitrogen214.00728.014
12.96%
13AlAluminiumAluminium126.98226.982
12.49%
1HHydrogenHydrogen81.0088.064
3.73%
Total216.110100.00%

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

From IMA formula

Synonyms

  • IMA2011-077
  • Thermessaiet-(NH4)
  • Unnamed (NH4-analogue of Thermessaite)

In other languages

German
IMA 2011-077 · Thermessait-(NH4)
Italian
thermessaite-(NH4)

Classification

Strunz
10th ed.

3.CG.25

  • 3HalidesClass
  • 3.CComplex halidesDivision
  • 3.CGAluminofluorides with CO3, SO4, PO4Group
  • 3.CG.25Thermessaite-(NH4)Species

Group, growth & confusion

Commonly confused with
1 mineral

Literature, links & citation

Citations
  1. 2012Williams, P. A., Hatert, F., Pasero, M., Mills, S. J. (2012) New minerals and nomenclature modifications approved in 2012. CNMNC Newsletter No 12. Mineralogical Magazine, 76 (1) 151-155 doi:10.1180/minmag.2012.076.1.151 DOI: 10.1180/minmag.2012.076.1.151
  2. 2015Witzke, T., de Wit, F., Kolitsch, U., Blaß, G. (2015) Mineralogy of the Burning Anna I Coal Mine Dump, Alsdorf, Germany. In Coal and Peat Fires: A Global Perspective- Case Studies – Coal Fires Vol. 3. Elsevier. p.203-240. doi:10.1016/C2010-0-68844-4DOI: 10.1016/C2010-0-68844-4
  3. 2017Garavelli, A., Pinto, D., Mitolo, D., Kolitsch, U (2017) Thermessaite-(NH4): another piece of the puzzle of the evolution of sublimate deposition at “La Fossa” crater fumaroles, in Abstract book. Joint SIMP-SGI-AIV-SoGeI 2017 Conference "Geosciences: a tool in a changing world", Società Geologica Italiana. Pisa, Italy. 122 doi:10.3301/ABSGI/2017.01DOI: 10.3301/ABSGI/2017.01
  4. 2021Garavelli, Anna, Pinto, Daniela, Mitolo, Donatella, Kolitsch, Uwe (2021) Thermessaite-(NH4), (NH4)2AlF3(SO4), a new fumarole mineral from La Fossa crater at Vulcano, Aeolian Islands, Italy. Mineralogical Magazine, 85 (5) 665-672 doi:10.1180/mgm.2021.69DOI: 10.1180/mgm.2021.69
  5. 2022(2022) Thermessaite-(NH4). Handbook of Mineralogy. Mineralogical Society of America
Cite this entry
@misc{mineral2026,
  author    = {Mineral Index editorial board},
  title     = {Thermessaite-(NH4) — Mineral Index},
  year      = {2026},
  url       = {https://mineralindex.org/minerals/thermessaite-nh4-39963},
  note      = {Accessed 2026-05-11}
}