Ilmenite
Ilmenite is a titanium-iron oxide mineral with the idealized formula FeTiO
3. It is a weakly magnetic black or steel-gray solid. Ilmenite is the most important ore of titanium and the main source of titanium dioxide, which is used in paints, printing inks, fabrics, plastics, paper, sunscreen, food and cosmetics.
| Ilmenite | |
|---|---|
Ilmenite from Miass, Ilmen Mts, Chelyabinsk Oblast', Southern Urals, Urals Region, Russia. 4.5 x 4.3 x 1.5 cm | |
| General | |
| Category | Oxide mineral |
| Formula (repeating unit) | Iron titanium oxide, FeTiO 3 |
| IMA symbol | Ilm |
| Strunz classification | 4.CB.05 |
| Dana classification | 04.03.05.01 |
| Crystal system | Trigonal |
| Crystal class | Rhombohedral (3) H-M symbol: (3) |
| Space group | R3 (no. 148) |
| Unit cell | a = 5.08854(7) c = 14.0924(3) [Å]: Z = 6 |
| Identification | |
| Color | Iron-black; gray with a brownish tint in reflected light |
| Crystal habit | Granular to massive and lamellar exsolutions in hematite or magnetite |
| Twinning | {0001} simple, {1011} lamellar |
| Cleavage | Absent; parting on {0001} and {1011} |
| Fracture | Conchoidal to subconchoidal |
| Tenacity | Brittle |
| Mohs scale hardness | 5–6 |
| Luster | Metallic to submetallic |
| Streak | Black |
| Diaphaneity | Opaque |
| Specific gravity | 4.70–4.79 |
| Optical properties | Uniaxial (–) |
| Birefringence | Strong; O: pinkish brown, E: dark brown (bireflectance) |
| Other characteristics | Weakly magnetic |
| References | |
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