Mineral Information and Data:

(Fe3+,Ni2+)8(OH,O)16Cl1.25 • nH2O [CNMNC approved formula]

Named for the locality: Akagane mine, Iwate Prefecture, Japan.

IMA status : Approved Species 1962 (IMA1962-004)
(8th edition) :  
  (06) Hydroxides and Oxides Containing Hydroxyl
  (06.01) where X+++O OH
(10th edition) :
  (04) Oxides and Hydroxides
  (04.D) Metal:Oxygen = 1:2 and similar
  (04.DK) With large (+- medium-sized) cations; tunnel structures
Crystal system: Monoclinic System
Point group (H-M): 2/m — prismatic
Unit cell: a = 10.561Å, b = 3.031Å, c = 10.483Å β = 90.63°
Crystal Habit: Tiny spindle-like quasi-single crystals are up to 5 μm in length; in bundles of such rods; commonly fine-grained massive to powdery.
Color: Yellowish brown
Diaphaneity: Semitransparent
Luster: Earthy
Hardness (Mohs): No data
Measured Density: No data g/cm3
Tenacity: No data
Streak: Brownish yellow
Geologic Setting: Apparently formed from pyrrhotite by ferric-sulfate-bearing solutions (Akagane mine, Japan); an important constituent in some soils, and certain geothermal brines and in sea-floor nodules; also formed as a corrosion product of some meteorites.
Mineral Association: Pyrrhotite (Akagane mine, Japan); hibbingite (Hibbing, Minnesota, USA)


Yellow to brownish masses of various amounts of akaganeite,
goethite and a spinel group mineral on Nantan meteorite.
All the minerals are confirmed by PXRD.
Origin: Nantan meteorites (Nandan meteorites), Lihu - Yaochai area, Nandan Co., Hechi Prefecture, Guangxi Zhuang Autonomous Region, China
Field of view is 4.5 mm.
Photo: © Łukasz Kruszewski (2007)