Taenite

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%.

Taenite
Widmanstätten patterns of kamacite and taenite, from a meteorite currently in the Natural History Museum, London.
General
Category	Metals and intermetallic alloys
Formula	γ-(Ni,Fe)
IMA symbol	Tae[1]
Strunz classification	1.AE.10
Crystal system	Isometric
Crystal class	Hexoctahedral (m3m) H-M symbol: (4/m 3 2/m)
Space group	Fm3m
Identification
Color	metallic grayish to white
Cleavage	None
Fracture	Hackly fracture
Tenacity	Malleable, flexible
Mohs scale hardness	5–5.5
Luster	metallic
Streak	light gray
Diaphaneity	Opaque
Specific gravity	7.8–8.22
Other characteristics	magnetic, not radioactive
References	[2][3]

Widmanstätten pattern showing the two forms of Nickel-Iron, Kamacite and Taenite, in an octahedrite meteorite

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

• Campo del Cielo strewn field in Argentina.
• Henbury Meteorites Conservation Reserve in Australia.
• Canyon Diablo in Arizona.

See also

• Glossary of meteoritics
• List of minerals