Editing Octahedrite (section)

==Structure==
{{see also|Widmanstätten pattern#Lamellæ formation mechanism|Widmanstätten pattern#Shape and orientation}}
Octahedrites derive their name from the crystal structure paralleling an [[octahedron]]. Opposite faces are parallel so, although an octahedron has 8 faces, there are only 4 sets of [[kamacite]] plates.

Due to a long cooling time in the interior of the parent [[asteroid]]s, these alloys have crystallized into intermixed millimeter-sized bands (from about 0.2&nbsp;mm to 5&nbsp;cm).<ref name=CdE2009>{{cite journal |title=Iron meteorites: Crystallization, thermal history, parent bodies, and origin |journal=Chemie der Erde – Geochemistry |volume=69 |issue=4 |pages=293–325 |doi=10.1016/j.chemer.2009.01.002 |year=2009 |last1=Goldstein|first1=J.I |last2=Scott|first2=E.R.D |last3=Chabot|first3=N.L |bibcode=2009ChEG...69..293G }}</ref> When polished and acid etched the classic [[Widmanstätten pattern]]s of intersecting lines of lamellar kamacite, are visible.

In gaps between the kamacite and taenite lamellae, a fine-grained mixture called [[plessite]] is often found.  An iron nickel phosphide, [[schreibersite]], is present in most nickel-iron meteorites, as well as an iron-nickel-[[cobalt]] [[carbide]], [[cohenite]]. [[Graphite]] and [[troilite]] occur in rounded nodules up to several cm in size.<ref name=him1975>Vagn F. Buchwald: Handbook of Iron Meteorites. University of California Press, 1975.</ref>