Akaganeite
A variety of Minerals
What is Akaganeite?
Akaganeite, also written as the deprecated Akaganéite, 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, so a more accurate formula is FeO0.833(OH)1.167Cl0.167. Nickel may substitute for iron, yielding the more general formula (Fe,Ni)8(OH,O)16Cl1.25 Akaganeite has a metallic luster and a brownish yellow streak. Its crystal structure is monoclinic and similar to that of hollandite BaMn8O16, 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.
Market Value Factors
Pricing varies for every rock and mineral, so use these universal factors to gauge Akaganeite before comparing listings or appraisals.
Size & Weight
Larger, intact specimens usually command higher prices.
Rarity & Demand
Scarce material or popular varieties sell at a premium.
Condition & Finish
Chips, repairs, and heavy wear lower value; clean prep helps.
Treatment & Provenance
Untreated specimens with documented locality are prized.
Akaganeite Localities Map
See where Akaganeite is found with a localities map, collecting zones, and geology context. Generate a sample map preview below.
Key Characteristics
Formation of Akaganeite
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. 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.
Quick Facts
Physical Properties
- Color
- Yellowish brown, rusty brown
- Density
- 3.52 g/cm³
- Streak
- Brownish yellow
Chemical Properties
- Chemical Formula
- (Fe3+,Ni2+)8(OH,O)16Cl1.25 · nH2O
- Elements
- Cl, Fe, H, Ni, O
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Akaganeite FAQs
How do I identify Akaganeite?
Akaganeite can be identified by its Yellowish brown color. Look for these key characteristics when examining specimens.
What color is Akaganeite?
Akaganeite typically appears in Yellowish brown, rusty brown. Color can vary depending on impurities and formation conditions.
What is the formation of akaganeite of Akaganeite?
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. 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.
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