Taenite
Widmanstätten patterns of kamacite and taenite, from a meteorite currently in the Natural History Museum, London.
General
CategoryMetals and intermetallic alloys
Formula
(repeating unit)		γ-(Ni,Fe)
IMA symbolTae[1]
Strunz classification1.AE.10
Crystal systemIsometric
Crystal classHexoctahedral (m3m)
H-M symbol: (4/m 3 2/m)
Space groupFm3m
Identification
Colormetallic grayish to white
CleavageNone
FractureHackly fracture
TenacityMalleable, flexible
Mohs scale hardness5–5.5
Lustermetallic
Streaklight gray
DiaphaneityOpaque
Specific gravity7.8–8.22
Other characteristicsmagnetic, not radioactive
References[2][3]
Widmanstätten pattern showing the two forms of Nickel-Iron, Kamacite and Taenite, in an octahedrite meteorite

Taenite is a mineral found naturally on Earth mostly in iron meteorites. It is an alloy of iron and nickel, with a chemical formula of Fe,Ni and nickel proportions of 20% up to 65%.

The name is derived from the Greek ταινία for "band, ribbon". Taenite is a major constituent of iron meteorites. In octahedrites it is found in bands interleaving with kamacite forming Widmanstätten patterns, whereas in ataxites it is the dominant constituent. In octahedrites a fine intermixture with kamacite can occur, which is called plessite.

Taenite is one of four known Fe-Ni meteorite minerals: The others are kamacite, tetrataenite, and antitaenite.

Properties

It is opaque with a metallic grayish to white color. The structure is isometric-hexoctahedral (cubic). Its density is around 8 g/cm3 and hardness is 5 to 5.5 on the Mohs scale. Taenite is magnetic, in contrast to antitaenite. The structure is isometric-hexoctahedral (cubic). The crystal lattice has the c≈a=3.582±0.002 Å.[4] The Strunz classification is I/A.08-20, while the Dana classification is 1.1.11.2.

Meteorite localities with taenite

See also

References

  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. ↑ Anthony, John W.; Bideaux, Richard A.; Bladh, Kenneth W.; Nichols, Monte C. (2005). "Taenite" (PDF). Handbook of Mineralogy. Mineral Data Publishing. Retrieved 14 March 2022.
  3. ↑ http://webmineral.com/data/Taenite.shtml Archived 2021-01-22 at the Wayback Machine Webmineral data
  4. ↑ Albertsen, F.; Knudsen, J. M.; Jensen, G. B. (Jun 1978). "Structure of taenite in two iron meteorites J.". Nature. 273 (5662): 453–454. Bibcode:1978Natur.273..453A. doi:10.1038/273453a0. S2CID 4177830.
  • Mason B., 1962: Meteorites. J. Wiley & Sons, New York
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