Feroxyhyte is an oxide/hydroxide of iron, δ-Fe3+O(OH). Feroxyhyte in the hexagonal system. It forms as brown rounded to concretionary masses. Feroxyhyte is opaque, magnetic, has a yellow streak, and has a relative density of 4.2.[
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It occurs in manganese-iron Manganese nodule on the Atlantic Ocean and Pacific Ocean floors. It is also found in the Baltic Sea, White Sea, and .[ It also occurs as cement and coatings on clasts in poorly drained soils and sediments, formed by the rapid Redox of iron(II) oxide compounds.][
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It was first described in 1976 for an occurrence in soils at its type locality: Kolomyya, Ivano-Frankivsk Oblast, Ukraine.[
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