Césarferreiraite

Fe2+Fe3+2(AsO4)2(OH)2 · 8H2O
IMA status
  • Approved
IMA symbol
Céf
IMA approved
2013
Also known as
  • Césarferreiraiet
  • IMA2012-099

Where it forms, where it's found

Geological setting

pegmatite

Type locality
Eduardo claim
  1. Barra do Cuieté
  2. Conselheiro Pena
  3. Minas Gerais
  4. Brazil

-19.0819°, -41.5100°

2recorded occurrences
Source · OpenStreetMap

Safety & handling

Physical

Transparency
Transparent
Colour
Pale to yellowish green
Streak
Pale to yellowish green
Cleavage
Distinct/Good

(010) (100)

Density
2.934 g/cm³

Optical

Optical type
Biaxial (+)
Notes

RI min=1.747 max=1.754

Crystallography

Crystal system
Triclinic
Space group
#2
Cell parameters
a = 5.383(2) Å · b = 6.878(2) Å · c = 10.364(3) Å
Cell angles
α = 96.43(4) ° · β = 102.29(2) ° · γ = 109.17(3) °
Ratio a:b:c
1 : 1.278 : 1.925
Z
1
Morphology

fibrous

Type-locality form

Single crystals, up to 10 μm long with a thickness of about 1-2 μm, are elongated along [001] and flattened on (100).

Chemical composition

Constituent elements
Mass composition breakdown
ElementAtoms At. mass g/mol Mass g/molMass share
8OOxygenOxygen1815.999287.982
46.19%
26FeIronIron355.845167.535
26.87%
33AsArsenicArsenic274.922149.844
24.03%
1HHydrogenHydrogen181.00818.144
2.91%
Total623.505100.00%

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

From IMA formula

Synonyms

  • Césarferreiraiet
  • IMA2012-099

In other languages

German
Césarferreirait · IMA 2012-099
Italian
césarferreiraite

Classification

Strunz
10th ed.

8.DC

  • 8Phosphates, Arsenates, VanadatesClass
  • 8.DPhosphates, etc. with additional anions, with H2ODivision
  • 8.DCWith only medium-sized cations, (OH, etc.):RO4 = 1:1 and < 2:1Group
  • 8.DCCésarferreiraiteSpecies

Group, growth & confusion

In the same group
1 members

Literature, links & citation

Citations
  1. 2013Williams, P. A., Hatert, F., Pasero, M., Mills, S. J. (2013) New minerals and nomenclature modifications approved in 2013. CNMNC Newsletter No 16. Mineralogical Magazine, 77 (6) 2695-2709 doi:10.1180/minmag.2013.077.6.01DOI: 10.1180/minmag.2013.077.6.01
  2. 2014Scholz, R., Chukanov, N. V., Filho, L. A. D. M., Atencio, D., Lagoeiro, L., Belotti, F. M., Chaves, M. L. S. C., Romano, A. W., Brandão, P. R., Belakovskiy, D. I., Pekov, I. (2014) Césarferreiraite, Fe2+Fe3+2(AsO4)2(OH)2·8H2O, from Eduardo mine, Conselheiro Pena, Minas Gerais, Brazil: Second arsenate in the laueite mineral group. American Mineralogist, 99 (4) 607-611 doi:10.2138/am.2014.4695 DOI: 10.2138/am.2014.4695
  3. 2017(2017) Césarferreiraite. Handbook of Mineralogy. Mineralogical Society of America
Cite this entry
@misc{mineral2026,
  author    = {Mineral Index editorial board},
  title     = {Césarferreiraite — Mineral Index},
  year      = {2026},
  url       = {https://mineralindex.org/minerals/cesarferreiraite-43865},
  note      = {Accessed 2026-05-11}
}