Feroxyhyte
Iron hydroxide mineral
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Feroxyhyte is an oxide/hydroxide of iron, δ-Fe3+O(OH). Feroxyhyte crystallizes in the hexagonal system. Feroxyhyte forms as brown, rounded to concretionary masses. Feroxyhyte is an opaque, magnetic mineral with a yellow streak and a relative density of 4.2.[3]
| Feroxyhyte | |
|---|---|
Image of Feroxyhyte | |
| General | |
| Category | Oxide mineral |
| Formula | δ-Fe3+O(OH) |
| IMA symbol | Fox[1] |
| Strunz classification | 4.FE.40 |
| Dana classification | 06.01.04.04 |
| Crystal system | Hexagonal Unknown space group |
| Unit cell | a = 2.95, c = 4.56 [Å]; z = 1 |
| Identification | |
| Formula mass | 88.85 g/mol |
| Color | Brown, yellow-brown |
| Crystal habit | Concretionary, massive, nodular |
| Streak | Yellow |
| Diaphaneity | Opaque |
| Specific gravity | 4.31 |
| Density | 4.2 |
| Optical properties | Uniaxial |
| References | [2][3][4] |
It occurs in manganese-iron nodules on the Atlantic and Pacific Ocean floors. It is also found in the Baltic, White, and Kara Seas.[5] Forms under high pressure conditions and reverts to goethite on exposure to surface conditions.[3] 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.[5]
It was first described in 1976 for an occurrence in soils at its type locality: Kolomyya, Ivano-Frankivsk Oblast, Ukraine.[2][5]