Editing Goethite (section)

== Formation ==
[[File:Geothite.jpg|thumb|A microscopic picture of Goethite (name misspelled on picture)]]
Goethite often forms through the [[weathering]] of other iron-rich minerals, and thus is a common component of [[soil]]s, concentrated in [[laterite]] soils. [[Nanoparticle|nanoparticulate]] [[authigenic]] goethite is a common [[Diagenesis|diagenetic]] iron oxyhydroxide in both marine and lake sediments.<ref>{{cite journal |doi=10.1130/G19924.1 |title=Nanogoethite is the dominant reactive oxyhydroxide phase in lake and marine sediments |journal=Geology |volume=31 |issue=11 |pages=993 |year=2003 |last1=Van Der Zee |first1=Claar |last2=Roberts |first2=Darryl R. |last3=Rancourt |first3=Denis G. |last4=Slomp |first4=Caroline P. |author-link=Caroline Slomp|bibcode=2003Geo....31..993V |hdl=1874/31393 |s2cid=130357956 |hdl-access=free }}</ref> The formation of goethite is marked by the oxidation state change of Fe<sup>2+</sup> (ferrous) to Fe<sup>3+</sup> (ferric), which allows for goethite to exist at surface conditions. Because of this oxidation state change, goethite is commonly seen as a [[pseudomorph]]. As iron-bearing minerals are brought to the zone of oxidation within the soil, the iron turns from iron(II) to iron(III), while the original shape of the parent mineral is retained. Common goethite pseudomorphs include [[pyrite]], [[siderite]], and [[marcasite]], though any iron(II)-bearing mineral could become a goethite pseudomorph if proper conditions are met. It may also be precipitated by [[groundwater]] or in other sedimentary conditions, or form as a primary mineral in [[hydrothermal]] deposits. Goethite has also been found to be produced by the excretion processes of certain bacteria types.<ref>{{cite journal |doi=10.1016/j.gca.2010.03.037 |title=Biomineralization of lepidocrocite and goethite by nitrate-reducing Fe(II)-oxidizing bacteria: Effect of pH, bicarbonate, phosphate, and humic acids |journal=Geochimica et Cosmochimica Acta |volume=74 |issue=13 |pages=3721–34 |year=2010 |last1=Larese-Casanova |first1=Philip |last2=Haderlein |first2=Stefan B. |last3=Kappler |first3=Andreas |bibcode=2010GeCoA..74.3721L }}</ref>