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Formula: NiFe
Carbide of nickel and iron
Crystal system: Isometric
Specific gravity: 7.70 calculated
Hardness: 5½ to 6
Colour: White
Magnetism: Strongly magnetic
Environments
Localities
The Barbianello meteorite, Barbianello, Pavia Province, Lombardy, Italy.
Haxonite is the second most common carbide in
meteorites,
following cohenite. Both
cohenite
and haxonite have been identified within a 2 cm single-crystal host of
taenite matrix. Both carbides form irregular-angular crystals associated
with nickelphosphide but have never been found in one inclusion
together. The Ni content in haxonite is close to 1.1 atoms per formula unit, which is a typical value for
all previously studied haxonites. Notably, no Ni-free haxonite crystals are known. It is suggested
that the presence of Ni stabilises the crystal structure of haxonite and makes it common in Ni-rich
irons. It is proposed that other factors promoting haxonite formation
include the presence of a precursor Ni-rich phase and relatively low crystallisation temperatures.
The meteorite is an iron ungrouped, Ni-rich ataxite
(AM 111.8.1308–1314).
There are two co-type localities, the Toluca meteorite, Jiquipilco, Mexico, Mexico, and the Canyon Diablo meteorite,
Meteor Crater area, Coconino County, Arizona, USA. They are both
iron octahedrites that fell about 10,000 and 50,000 years
ago, respectively
(Wiki).
At the type localities, haxonite forms intricate intergrowths with
taenite, schreibersite and
kamacite
(Mindat).
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