Hematite

Iron Rose St Christophe-en-Oisans, Bourg d’Oisans, Isère, Rhône-Alpes, France © JM. Johannet

Chemical Formula: Fe2O3
Locality: Matto Grosso, Brazil. Mesabi iron ore range, Minnesota, USA.
Name Origin: From the Greek, haimatites, “bloodlike'” in allusion to vivid red color of the powder.

Hematite, also spelled as haematite, is the mineral form of iron(III) oxide (Fe2O3), one of several iron oxides. Hematite crystallizes in the rhombohedral lattice system, and it has the same crystal structure as ilmenite and corundum. Hematite and ilmenite form a complete solid solution at temperatures above 950 °C (1,740 °F).

Hematite is a mineral, colored black to steel or silver-gray, brown to reddish brown, or red. It is mined as the main ore of iron. Varieties include kidney ore, martite (pseudomorphs after magnetite), iron rose and specularite (specular hematite). While the forms of hematite vary, they all have a rust-red streak. Hematite is harder than pure iron, but much more brittle. Maghemite is a hematite- and magnetite-related oxide mineral.

Huge deposits of hematite are found in banded iron formations. Gray hematite is typically found in places where there has been standing water or mineral hot springs, such as those in Yellowstone National Park in North America. The mineral can precipitate out of water and collect in layers at the bottom of a lake, spring, or other standing water. Hematite can also occur without water, however, usually as the result of volcanic activity.

Clay-sized hematite crystals can also occur as a secondary mineral formed by weathering processes in soil, and along with other iron oxides or oxyhydroxides such as goethite, is responsible for the red color of many tropical, ancient, or otherwise highly weathered soils.

Physical Properties

Cleavage: None
Color: Reddish gray, Black, Blackish red.
Density: 5.3
Diaphaneity: Subtranslucent to opaque
Fracture: Conchoidal – Fractures developed in brittle materials characterized by smoothly curving surfaces, (e.g. quartz).
Hardness: 6.5 – Pyrite
Luminescence: Non-fluorescent.
Luster: Metallic
Magnetism: Magnetic after heating
Streak: reddish brown

Photos :

Hematite (var. Iron Rose), quartz and chlorite Fibbia – Fontana – Central St Gotthard Massif – Leventina – Ticino – Switzerland Specimen weight:155 gr. Crystal size:mm. 16 Overall size: 63mm x 42 mm x 41 mm © minservice
Hematite (pseudocubic) Ouro Preto, Minas Gerais, Brazil Small Cabinet, 6.9 x 6.2 x 2.8 cm © irocks
Hematite (twin!) N’Chwaning II Mine, Kuruman, Kalahari manganese fields, Northern Cape Province, South Africa Size: 4.0 x 2.5 x 1.5 cm (miniature) © danweinrich
Hematite San Carlos, Chihuahua, Mexico Miniature, 2.9 x 2.0 x 0.9 cm © irocks
SHARE