[8] The heat released from the radioactive decay of the short-lived nuclides 26Al and 60Fe is considered as a plausible cause for the melting and differentiation of their parent bodies in the early Solar System.

[11] The IIE iron meteorites may be a notable exception, in that they probably originate from the crust of S-type asteroid 6 Hebe.

Minor minerals, when occurring, often form rounded nodules of troilite or graphite, surrounded by schreibersite and cohenite.

Schreibersite and troilite also occur as plate shaped inclusions, which show up on cut surfaces as cm-long and mm-thick lamellae.

[16] The older structural classification is based on the presence or absence of the Widmanstätten pattern, which can be assessed from the appearance of polished cross-sections that have been etched with acid.

The categories are: A newer chemical classification scheme based on the proportions of the trace elements Ga, Ge and Ir separates the iron meteorites into classes corresponding to distinct asteroid parent bodies.

[19] This classification is based on diagrams that plot nickel content against different trace elements (e.g. Ga, Ge and Ir).