This article has an unclear
citation style. (March 2019) |
Akaganeite | |
---|---|
General | |
Category | Oxide mineral |
Formula (repeating unit) | Fe3+O(OH,Cl) |
IMA symbol | Akg [1] |
Strunz classification | 4.DK.05 |
Crystal system | Monoclinic |
Crystal class | Prismatic (2/m) (same H-M symbol) |
Space group | I2/m |
Unit cell | a = 10.561, b = 3.031 c = 10.483 [Å]; β = 90.63°; Z = 1 |
Identification | |
Color | Yellowish brown, rusty brown |
Luster | Earthy |
Streak | Brownish yellow |
Diaphaneity | Transparent, translucent |
Specific gravity | 3.52 |
Akaganeite, also written as the deprecated Akaganéite, [2] is a chloride-containing iron(III) oxide-hydroxide mineral, formed by the weathering of pyrrhotite (Fe1−xS).
Akaganeite is often described as the β phase of
anhydrous
ferric oxyhydroxide FeOOH, but some
chloride (or
fluoride) ions are normally included in the structure,
[3] so a more accurate formula is FeO
0.833(OH)
1.167Cl
0.167.
[4]
Nickel may substitute for iron, yielding the more general formula (Fe3+
,Ni2+
)
8(OH,O)
16Cl
1.25
[5]
Akaganeite has a
metallic
luster and a brownish yellow
streak. Its
crystal structure is
monoclinic and similar to that of
hollandite BaMn
8O
16, 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.
[4]
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, [6] but named as early as 1961. [7] [8]
Akaganeite has also been found in widely dispersed locations around the world and in rocks from the Moon that were brought back during the Apollo Project. The occurrences in meteorites and the lunar sample are thought to have been produced by interaction with Earth's atmosphere. It has been detected on Mars through orbital imaging spectroscopy. [9]
This article has an unclear
citation style. (March 2019) |
Akaganeite | |
---|---|
General | |
Category | Oxide mineral |
Formula (repeating unit) | Fe3+O(OH,Cl) |
IMA symbol | Akg [1] |
Strunz classification | 4.DK.05 |
Crystal system | Monoclinic |
Crystal class | Prismatic (2/m) (same H-M symbol) |
Space group | I2/m |
Unit cell | a = 10.561, b = 3.031 c = 10.483 [Å]; β = 90.63°; Z = 1 |
Identification | |
Color | Yellowish brown, rusty brown |
Luster | Earthy |
Streak | Brownish yellow |
Diaphaneity | Transparent, translucent |
Specific gravity | 3.52 |
Akaganeite, also written as the deprecated Akaganéite, [2] is a chloride-containing iron(III) oxide-hydroxide mineral, formed by the weathering of pyrrhotite (Fe1−xS).
Akaganeite is often described as the β phase of
anhydrous
ferric oxyhydroxide FeOOH, but some
chloride (or
fluoride) ions are normally included in the structure,
[3] so a more accurate formula is FeO
0.833(OH)
1.167Cl
0.167.
[4]
Nickel may substitute for iron, yielding the more general formula (Fe3+
,Ni2+
)
8(OH,O)
16Cl
1.25
[5]
Akaganeite has a
metallic
luster and a brownish yellow
streak. Its
crystal structure is
monoclinic and similar to that of
hollandite BaMn
8O
16, 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.
[4]
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, [6] but named as early as 1961. [7] [8]
Akaganeite has also been found in widely dispersed locations around the world and in rocks from the Moon that were brought back during the Apollo Project. The occurrences in meteorites and the lunar sample are thought to have been produced by interaction with Earth's atmosphere. It has been detected on Mars through orbital imaging spectroscopy. [9]