Nannoniite

Al2(OH)5F
IMA status
  • Approved
IMA symbol
Nnn
Also known as
  • IMA2024-010
  • Nannoniiet
  • UM1990-28-OHF:Al

Where it forms, where it's found

Type locality
Le Cetine di Cotorniano mine
  1. Chiusdino
  2. Siena Province
  3. Tuscany
  4. Italy

43.2320°, 11.1683°

4recorded occurrences
Source · OpenStreetMap

Physical

Hardness
123456789102 – 3/ 10 MOHS
  1. 1Talc
  2. 2Gypsum
  3. 3Calcite
  4. 4Fluorite
  5. 5Apatite
  6. 6Orthoclase
  7. 7Quartz
  8. 8Topaz
  9. 9Corundum
  10. 10Diamond
Colour
colourless to white
Streak
white
Tenacity
brittle
Cleavage
Perfect

(001)

Density
2.492 g/cm³

Optical

UV response
shows a bluish-white fluorescence under shortwave UV radiation (λ=254 nm) and a yellowish-white fluorescence under longwave UV radiation (λ=350 nm).
Notes

The mean refractive index, calculated according to the Gladstone–Dale relationship, is 1.564.

Crystallography

Crystal system
Monoclinic
Space group
#14
Cell parameters
a = 8.688(3) Å · b = 5.024(2) Å · c = 9.734(4) Å
Cell angles
β = 90.77(2) °
Ratio a:b:c
1 : 0.578 : 1.120
Z
4
Type-locality form

occurs as (hemi-)spherical aggregates, up to 1 mm in diameter, formed by spindle-like crystals or tabular individuals.

Comment

P21/n

Crystal structure

Chemical composition

Constituent elements
Mass composition breakdown
ElementAtoms At. mass g/mol Mass g/molMass share
8OOxygenOxygen515.99979.995
50.63%
13AlAluminiumAluminium226.98253.964
34.16%
9FFluorineFluorine118.99818.998
12.02%
1HHydrogenHydrogen51.0085.040
3.19%
Total157.997100.00%

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

From Mindat formula

Synonyms

  • IMA2024-010
  • Nannoniiet
  • UM1990-28-OHF:Al

In other languages

German
Nannoniit

Classification

Strunz
10th ed.

4.FE

  • 4OxidesClass
  • 4.FHydroxides (without V or U)Division
  • 4.FEHydroxides with OH, without H2O; sheets of edge-sharing octahedraGroup
  • 4.FENannoniiteSpecies

Literature, links & citation

Citations
  1. 1968Sabina, Ann P., Jambor, John L., Plant, A. G. (1968) Weloganite, a new strontium zirconium carbonate from Montreal Island, Canada. The Canadian Mineralogist, 9 (4) 468-477
  2. 1990Jambor, John L.; Sabina, Ann P.; Ramik, Robert A.; Sturman, B. Drako (1990) A fluorine-bearing gibbsite-like mineral from the Francon quarry, Montreal, Quebec. The Canadian Mineralogist, 28 (1). 147-153
  3. 2024Biagioni, C., Mugnaioli, E., Lorenzon, S., Mauro, D., Musetti, S., Sejkora, J., Belmonte, D., Demitri, N., Dolnı́ček, Z. (2024) Nannoniite, Al₂(OH)₅F, a new mineral from the Cetine di Cotorniano mine (Tuscany, Italy). European Journal of Mineralogy, 36 (6). 1011-1022 doi:10.5194/ejm-36-1011-2024DOI: 10.5194/ejm-36-1011-2024
Cite this entry
@misc{mineral2026,
  author    = {Mineral Index editorial board},
  title     = {Nannoniite — Mineral Index},
  year      = {2026},
  url       = {https://mineralindex.org/minerals/nannoniite-471229},
  note      = {Accessed 2026-05-11}
}