Ferrihydrite

Ferrihydrite
Mine drainage from Ohio. The orange coating on the logs is ferrihydrite.
General
CategoryOxide minerals
Formula
(repeating unit)		(Fe3+)2O3·0.5H2O
IMA symbolFhy[1]
Strunz classification4.FE.35
Dana classification04.03.02.02
Crystal systemHexagonal
Crystal classDihexagonal pyramidal (6mm)
H-M symbol: (6mm)
Space groupP63mc
Unit cella = 5.958, c = 8.965 [Å]; Z = 1
Identification
Formula mass168.70 g/mol
ColorDark brown, yellow-brown
Crystal habitAggregates, microscopic crystals
StreakYellow-brown
DiaphaneityOpaque
Density3.8 g/cm3
References[2][3][4][5]
X-ray diffraction patterns for six-line and two-line ferrihydrite.
X-ray diffraction patterns for six-line (top) and two-line (bottom) ferrihydrite. Cu Kα radiation.

Ferrihydrite (Fh) is a widespread hydrous ferric oxyhydroxide mineral at the Earth's surface,[6][7] and a likely constituent in extraterrestrial materials.[8] It forms in several types of environments, from freshwater to marine systems, aquifers to hydrothermal hot springs and scales, soils, and areas affected by mining. It can be precipitated directly from oxygenated iron-rich aqueous solutions, or by bacteria either as a result of a metabolic activity or passive sorption of dissolved iron followed by nucleation reactions.[9] Ferrihydrite also occurs in the core of the ferritin protein from many living organisms, for the purpose of intra-cellular iron storage.[10][11]

  1. ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
  2. ^ "Ferrihydrite Mineral Data". webmineral.com. Retrieved 2011-10-24.
  3. ^ "Ferrihydrite mineral information and data". mindat.org. Retrieved 2011-10-24.
  4. ^ "Handbook of Mineralogy" (PDF). Archived from the original (PDF) on 2012-07-16. Retrieved 2011-10-24.
  5. ^ Mineralienatlas
  6. ^ J. L. Jambor, J.E. Dutrizac, Chemical Reviews, 98, 22549–2585 (1998)
  7. ^ R. M. Cornell R.M., U. Schwertammn, The iron oxides: structure, properties, reactions, occurrences and uses, Wiley–VCH, Weinheim, Germany (2003)
  8. ^ M. Maurette, Origins of Life and Evolution of the Biosphere, 28, 385–412 (1998)
  9. ^ D. Fortin, S. Langley, Earth-Science Reviews, 72, 1–19 (2005)
  10. ^ N. D. Chasteen, P. M. Harrison, Journal of Structural Biology, 126, 182–194 (1999)
  11. ^ A. Lewin, G. R. Moore, N. E. Le Brun, Dalton Transactions, 22, 3597–3610 (2005)