Trevorite
Rare nickel iron oxide mineral / From Wikipedia, the free encyclopedia
Trevorite is a rare nickel iron oxide mineral belonging to the spinel group. It has the chemical formula NiFe3+2O4. It is a black mineral with the typical spinel properties of crystallising in the cubic system, black streaked, infusible and insoluble in most acids.
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Trevorite | |
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General | |
Category | Oxide minerals Spinel group Spinel structural group |
Formula (repeating unit) | NiFe3+2O4 |
IMA symbol | Trv[1] |
Strunz classification | 4.BB.05 |
Dana classification | 7.2.2.5 |
Crystal system | Cubic |
Crystal class | Hexoctahedral (m3m) H-M symbol: (4/m 3 2/m) |
Space group | Fd3m (no. 227) |
Unit cell | a = 8.41 Å; Z = 8 |
Identification | |
Color | Black, greenish hue |
Crystal habit | Granular to massive, rare as minute octahedra |
Cleavage | None |
Fracture | Uneven |
Tenacity | Brittle |
Mohs scale hardness | 5 |
Luster | Metallic to sub-metallic |
Streak | Brown |
Diaphaneity | Opaque, transparent in thinnest fragments |
Specific gravity | 5.164 |
Refractive index | n = 2.41 (calculated) |
Other characteristics | Highly magnetic |
References | [2][3][4] |
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There is at least partial solid solution between trevorite and magnetite, with many magnetites from ultramafic rocks containing at least trace amounts of Ni. Fe2+ and Mg2+ may substitute for Ni in trevorite.