Tetrataenite
| Tetrataenite | |
|---|---|
Silvery-bright tetrataenite crystals | |
| General | |
| Category | Native element minerals |
| Formula | FeNi |
| IMA symbol | Ttae |
| Strunz classification | 1.AE.10 |
| Crystal system | Tetragonal |
| Crystal class | Domatic (m) (same H-M symbol) |
| Space group | P4/mmm |
| Unit cell | 22.92 ų |
| Identification | |
| Formula mass | 57.27 gm |
| Color | gray white, silver white |
| Crystal habit | Granular – Common texture observed in granite and other igneous rock |
| Cleavage | none |
| Fracture | malleable |
| Mohs scale hardness | 3.5 |
| Luster | metallic |
| Streak | gray |
| Diaphaneity | opaque |
| Density | 8.275 |
| Common impurities | Co, Cu, P |
| References | |
Tetrataenite is a native metal alloy composed of chemically-ordered L10-type FeNi, recognized as a mineral in 1980. The mineral is named after its tetragonal crystal structure and its relation to the iron-nickel alloy, taenite, which is chemically disordered (A1) phase with an underlying fcc lattice. Tetrataenite is one of the mineral phases found in meteoric iron. Before its discovery in meteoritic samples, experimental synthesis of the L10 phase was first reported in 1962 by Louis Néel and co-workers, following neutron irradiation of a chemically disordered FeNi sample under an applied magnetic field. Compared to the magnetically soft, chemically disordered A1 phase (taenite), the tetragonal L10 structure of tetrataenite leads to good hard magnetic properties, including a large uniaxial magnetocrystalline anisotropy energy. Consequently, it is under consideration for applications as a rare-earth-free permanent magnet.