Class: Oxides & hydroxides
Group: Hematite
Original description: unknown [prehistoric].
Type locality: unknown [prehistoric].
Type material: unknown.
Etymology: from the Ancient Greek αἱματίτης (haimatites), bloodlike, in allusion to vivid red colour of the powder.
Distribution: widespread. Algeria: Nador; Brazil: Bahia, Itabira and Brumado mine; Minas Gerais, Mesa Redonda and Congonhas do Campo; England: Cumbria, Cleator Moor; Italy: Elba, Rio Marina; Norway: Kragerø and Hiassen; Romania: Ocna de Fier; South Africa: North Cape, Kuruman district; Switzerland: St Gotthard, Uri; Binntal, Valais; and many other places; USA: Arizona, La Paz Co., near Quartzsite; Utah, Juab Co., Thomas Range (
Anthony et al., 2001—2005).
Chemistry
Fe2O3
Essential elements: oxygen (O), iron (Fe).
Crystal data
Crystallography: trigonal — hexagonal scalenohedral.
Crystal habit: crystals complex rhombohedral, pseudocubic, prismatic, rarely scalenohedral, to 13 cm, with triangular striations on {0001} and {1011}; thin tabular, to micaceous or platy, commonly in rosettes; radiating fibrous, reniform, botryoidal or stalactitic masses, columnar; earthy, granular, oolitic, concretionary.
Twinning: penetration twins on {0001} or with {1010} as composition plane; also lamellar on {1011} (
Anthony et al., 2001—2005).
Optical properties
Colour: steel-grey, may have iridescent tarnish, dull to bright red; white to grey-white, with a bluish tint, in reflected light with deep blood-red internal reflections (
Anthony et al., 2001—2005).
Diaphaneity: оpaque; translucent on thin edges (
Anthony et al., 2001—2005).
Lustre: metallic or submetallic to dull (
Anthony et al., 2001—2005).
Refractive index: 2.69—3.22 — anisotropic [uniaxial (-)] (
Lazzarelli, 2012).
Birefringence: 0.28.
Dispersion: very strong (
Anthony et al., 2001—2005).
Pleochroism: weak; O = brownish red; E = yellowish red (
Anthony et al., 2001—2005).
Material from ‘Repository’