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Chemical composition Fe2O3
Crystal system Trigonal
Habit Tabular to thick crystals; micaceous or platy, commonly in rosettes; radiating fibrous, reniform, botryoidal or stalactitic masses, columnar; earthy, granular, oolitic
Cleavage None, may show partings on {0001} and {1011}
Fracture Uneven to sub-conchoidal
Hardness 5.5–6.5
Refractive index nω = 3.150–3.220, nε = 2.870–2.940
Specific gravity 5.26
Lustre Metallic