Feroxyhyte
Template:Short description Template:Infobox mineral Feroxyhyte is an oxide/hydroxide of iron, δ-Fe3+O(OH). Feroxyhyte crystallizes in the hexagonal system. It forms as brown, rounded to concretionary masses. Feroxyhyte is an opaque, magnetic mineral with a yellow streak and a relative density of 4.2.<ref name="Webmin" />
It occurs in manganese-iron nodules on the Atlantic and Pacific Ocean floors. It is also found in the Baltic, White, and Kara Seas.<ref name="Handbook">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Forms under high pressure conditions and reverts to goethite on exposure to surface conditions.<ref name="Webmin" /> It also occurs as cement and coatings on clasts in poorly drained soils and sediments, formed by the rapid oxidation of iron(II) oxide compounds.<ref name="Handbook" />
It was first described in 1976 for an occurrence in soils at its type locality: Kolomyya, Ivano-Frankivsk Oblast, Ukraine.<ref name="Mindat" /><ref name="Handbook" />