Haematite, is the mineral form o airn(III) oxide (Fe2O3), ane o several airn oxides.
Haematite | |
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Brazilian trigonal haematite crystal | |
General | |
Category | Oxide minerals |
Formula (repeatin unit) | airn(III) oxide, Fe2O3, α-Fe2O3 |
Strunz clessification | 04.CB.05 |
Creestal seestem | Trigonal |
Space group | Trigonal hexagonal scalenohedral H-M symbol: (32/m) Space group: R3c |
Unit cell | a = 5.038(2) Å, c = 13.772(12) Å; Z = 6 |
Identification | |
Colour | Metallic gray, dull tae bricht reid |
Creestal habit | Tabular tae thick crystals; micaceous or platy, commonly in rosettes; radiatin fibrous, reniform, botryoidal or stalactitic masses, columnar; yirdy, granular, oolitic |
Twinnin | Penetration an lamellar |
Cleavage | None, mey shaw pairtins on {0001} an {1011} |
Fractur | Uneven tae sub-conchoidal |
Tenacity | Brickle |
Mohs scale haurdness | 5.5–6.5 |
Skinkle | Metallic tae splendent |
Streak | Bricht reid tae mirk reid |
Diaphaneity | Opaque |
Speceefic gravity | 5.26 |
Optical properties | Uniaxial (-) |
Refractive index | nω = 3.150–3.220, nε = 2.870–2.940 |
Birefringence | δ = 0.280 |
Pleochroism | O = brounish reid; E = yellaeish reid |
References |
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