Ilmenite | |
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General | |
Category | Oxide mineral |
Formula (repeating unit) | Iron titanium oxide, FeTiO 3 |
IMA symbol | Ilm[1] |
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 | [2][3][4] |
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[5] and the main source of titanium dioxide, which is used in paints, printing inks,[6] fabrics, plastics, paper, sunscreen, food and cosmetics.[7]