Akaganeite, also written as the deprecated Akaganéite,Ernst A.J. Burke (2008):
Tidying up Mineral Names: an IMA-CNMNC Scheme for Suffixes, Hyphens and Diacritical marks
. ''Mineralogical Record'', volume 39, issue 2. is a

chloride The chloride ion is the anion (negatively charged ion) Cl−. It is formed when the element chlorine (a halogen) gains an electron or when a compound such as hydrogen chloride is dissolved in water or other polar solvents. Chloride s ...

-containing iron(III) oxide-hydroxide

mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. ...

, formed by the weathering of

pyrrhotite Pyrrhotite is an iron sulfide mineral with the formula Fe(1-x)S (x = 0 to 0.2). It is a nonstoichiometric variant of FeS, the mineral known as troilite. Pyrrhotite is also called magnetic pyrite, because the color is similar to pyrite and it ...

(Fe_1−''x''S). Akaganeite is often described as the β phase of

anhydrous A substance is anhydrous if it contains no water. Many processes in chemistry can be impeded by the presence of water; therefore, it is important that water-free reagents and techniques are used. In practice, however, it is very difficult to achi ...

ferric oxyhydroxide , but some

(or

fluoride Fluoride (). According to this source, is a possible pronunciation in British English. is an inorganic, monatomic anion of fluorine, with the chemical formula (also written ), whose salts are typically white or colorless. Fluoride salts ...

) ions are normally included in the structure,Jongsik Kim and Clare P. Grey (2010), "Li Solid-State MAS NMR Study of Local Environments and Lithium Adsorption on the Iron(III) Oxyhydroxide, Akaganeite (β-FeOOH)". ''Chemistry of Materials'', volume 22, pages 5453–5462. so a more accurate formula is .C. Rémazeilles and Ph. Refait (2007):
On the formation of β-FeOOH (akaganéite) in chloride-containing environments
. ''Corrosion Science'', volume 49, issue 2, pages 844-857.

Nickel Nickel is a chemical element with symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel is a hard and ductile transition metal. Pure nickel is chemically reactive but large pieces are slow ...

may substitute for iron, yielding the more general formula Mineral 314-687: Akaganeite
. ''Mindat.org'' database, accessed on 2019-02-12. Akaganeite has a

metal A metal (from Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. Metals are typi ...

lic luster and a brownish yellow streak. Its

crystal structure In crystallography, crystal structure is a description of the ordered arrangement of atoms, ions or molecules in a crystalline material. Ordered structures occur from the intrinsic nature of the constituent particles to form symmetric patterns t ...

monoclinic In crystallography, the monoclinic crystal system is one of the seven crystal systems. A crystal system is described by three vectors. In the monoclinic system, the crystal is described by vectors of unequal lengths, as in the orthorhombic ...

and similar to that of hollandite , characterised by the presence of tunnels parallel to the c-axis of the tetragonal lattice. These tunnels are partially occupied by chloride anions that give to the crystal its structural stability.

Occurrence

The mineral was discovered in the Akagane mine in Iwate, Japan, for which it is named. It was described by the Japanese mineralogist Matsuo Nambu in 1968, but named as early as 1961. Alan Lindsay Mackay (1962): "β-ferric oxyhydroxide - akaganéite", in ''Mineralogical Magazine and Journal of the Mineralogical Society'', volume 33, issue 259, pages 270-280. Cites a private communication by Matsuo Nambu (1961). Note: the diacritic in the title is incorrect, see Burke (2008). Reviewed by Mandarino (1963) in ''American Minralogist''J. A. Mandarino (1963):
New Mineral Names: Akaganéite
. ''American Mineralogist'', volume 48, issues 5-6, page 711. Short review of Mackay's communication (1962) in ''Mineralogical Magazine''. Note: the diacritic in the title is incorrect. Akaganeite has also been found in widely dispersed locations around the world and in rocks from the

Moon The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width ...

that were brought back during the Apollo Project. The occurrences in

meteorite A meteorite is a solid piece of debris from an object, such as a comet, asteroid, or meteoroid, that originates in outer space and survives its passage through the atmosphere to reach the surface of a planet or moon. When the original object en ...

s and the lunar sample are thought to have been produced by interaction with

Earth's atmosphere The atmosphere of Earth is the layer of gases, known collectively as air, retained by Earth's gravity that surrounds the planet and forms its planetary atmosphere. The atmosphere of Earth protects life on Earth by creating pressure allowing f ...

. It has been detected on Mars through orbital imaging spectroscopy.

References

External links

Mindat with locationsWebmineral
Iron(III) minerals Halide minerals Oxide minerals Monoclinic minerals Minerals in space group 12 Minerals described in 1968 {{Oxide-mineral-stub

Occurrence

See also

References

External links