Olsenite

KFe4(PO4)3
IMA status
  • Approved
IMA symbol
Ose
Also known as
  • Olseniet

Where it forms, where it's found

Geological setting

IAB Complex iron meteorite

Type locality
El Ali meteorite
  1. Hiran Region
  2. Somalia

4.2881°, 44.8983°

1recorded occurrences
Source · OpenStreetMap

Physical

Density
3.52 g/cm³

Optical

Notes

The Gladstone-Dale relationship gives n = 1.66

Crystallography

Crystal system
Orthorhombic
Space group
Pnnm
Cell parameters
a = 9.81(1) Å · b = 16.51(1) Å · c = 6.27(1) Å
Ratio a:b:c
1 : 1.683 : 0.639
Z
4
Type-locality form

irregular crystals, 1 to 5 μm in size

Comment

Electron backscatter diffraction

Crystal structure

Chemical composition

Constituent elements
Mass composition breakdown
ElementAtoms At. mass g/mol Mass g/molMass share
26FeIronIron455.845223.380
40.81%
8OOxygenOxygen1215.999191.988
35.07%
15PPhosphorusPhosphorus330.97492.922
16.98%
19KPotassiumPotassium139.09839.098
7.14%
Total547.388100.00%

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

From IMA formula

Synonyms

  • Olseniet

In other languages

French
olsénite
German
IMA 2022-100 · Olsenit
Italian
Olsenite
Japanese
オルセン石

Classification

Strunz
10th ed.

8.AB

  • 8Phosphates, Arsenates, VanadatesClass
  • 8.APhosphates, etc. without additional anions, without H2ODivision
  • 8.ABWith medium-sized cationsGroup
  • 8.ABOlseniteSpecies

Literature, links & citation

Citations
  1. 2023Ma, C, Herd, CDK, Locock, AJ (2023) Nanomineralogy of the El Ali Meteorite: Discovery of Olsenite, KFe4 (PO4) 3, the Third New Mineral from this IAB Iron. LPI Contributions, 2806. 1883
  2. 2023Bosi, Ferdinando; Miyawaki, Ritsuro; Hatert, Frédéric; Pasero, Marco; Mills, Stuart J. (2023) IMA Commission on New Minerals, Nomenclature and Classification (CNMNC) – Newsletter 71. European Journal of Mineralogy, 35 (1). 75-79 doi:10.5194/ejm-35-75-2023 DOI: 10.5194/ejm-35-75-2023
  3. 2024Herd, Christopher DK, Ma, Chi, Locock, Andrew J, Saini, Radhika, Walton, Erin L (2024) Three new iron-phosphate minerals from the El Ali iron meteorite, Somalia: Elaliite F e 8 2+ Fe3+ (PO4) O8, elkinstantonite Fe4 (PO4) 2O, and olsenite KFe4 (PO4) 3. American Mineralogist, 109 (12). 2142-2151
Cite this entry
@misc{mineral2026,
  author    = {Mineral Index editorial board},
  title     = {Olsenite — Mineral Index},
  year      = {2026},
  url       = {https://mineralindex.org/minerals/olsenite-470466},
  note      = {Accessed 2026-05-11}
}