Editing Iron (section)

===Metallic iron===
[[File:Widmanstatten hand.jpg|thumb| right| A polished and chemically etched piece of an iron meteorite, believed to be similar in composition to the Earth's metallic core, showing individual crystals of the iron-nickel alloy ([[Widmanstatten pattern]])]]
Metallic or [[native iron]] is rarely found on the surface of the Earth because it tends to oxidize. However, both the Earth's [[inner core|inner]] and [[outer core]], which together account for 35% of the mass of the whole Earth, are believed to consist largely of an iron alloy, possibly with [[nickel]]. Electric currents in the liquid outer core are believed to be the origin of the [[Earth's magnetic field]]. The other [[terrestrial planet]]s ([[Mercury (planet)|Mercury]], [[Venus (planet)|Venus]], and [[Mars (planet)|Mars]]) as well as the [[Moon]] are believed to have a metallic core consisting mostly of iron. The [[M-type asteroid]]s are also believed to be partly or mostly made of metallic iron alloy.

The rare [[iron meteorite]]s are the main form of natural metallic iron on the Earth's surface. Items made of [[cold forging|cold-worked]] meteoritic iron have been found in various archaeological sites dating from a time when iron smelting had not yet been developed; and the [[Inuit people|Inuit]] in [[Greenland]] have been reported to use iron from the [[Cape York meteorite]] for tools and hunting weapons.<ref>{{cite journal|last=Buchwald |first= V F| title = On the Use of Iron by the Eskimos in Greenland| journal = Materials Characterization| volume = 29| issue = 2| year = 1992 | pages = 139–176 | doi = 10.1016/1044-5803(92)90112-U }}</ref> About 1 in 20 [[meteorite]]s consist of the unique iron-nickel minerals [[taenite]] (35–80% iron) and [[kamacite]] (90–95% iron).<ref>{{Cite book |url={{Google books|QDU7AAAAIAAJ|page=PA152|keywords=|text=|plainurl=yes}} |page=152 |title=Planet earth: cosmology, geology, and the evolution of life and environment |publisher=Cambridge University Press|first=Cesare|last=Emiliani |date=1992 |isbn=978-0-521-40949-0 |bibcode=1992pecg.book.....E}}</ref> Native iron is also rarely found in basalts that have formed from magmas that have come into contact with carbon-rich sedimentary rocks, which have reduced the oxygen [[fugacity]] sufficiently for iron to crystallize. This is known as [[telluric iron]] and is described from a few localities, such as [[Disko Island]] in West Greenland, [[Sakha Republic|Yakutia]] in [[Russia]] and [[Bühl (Baden)|Bühl]] in [[Germany]].<ref name="Pernet-Fisher_etal_2017">{{Cite journal |last1=Pernet-Fisher |first1=J. |last2=Day |first2=J.M.D. |last3=Howarth |first3=G.H. |last4=Ryabov |first4=V.V. |last5=Taylor |first5=L.A. |date=2017 |title=Atmospheric outgassing and native-iron formation during carbonaceous sediment–basalt melt interactions |url=https://www.researchgate.net/publication/312455203 |journal=Earth and Planetary Science Letters |volume=460 |pages=201–212 |doi=10.1016/j.epsl.2016.12.022|bibcode=2017E&PSL.460..201P |doi-access=free }}</ref>