Hematite

Hematite is commonly known as ‘red iron ore’, and it is composed of Fe₂O₃. It contains 70% iron and belongs to the trigonal system. The crystals are blocky or rhombic and sometimes have columnar or conical shapes. The blocky crystal aggregates form a rosette pattern that is called ‘iron rose’. Haematite crystals are mainly platy, dense, columnar, fibrous, reniform, botryoidal, stalactitic, dendritic or granular. When hematite is reniform, it is called ‘kidney ore’. It has several colours, such as light brown, bright red, blood red, brownish red, grey and iron black. It has brownish red streaks, opaque diaphaneity, a metallic to dark lustre, a specific gravity of 5.26, a Mohs hardness of 5–6, and uneven to sub-conchoidal fractures. It usually forms in hydrothermal metasomatic ore deposits and can also be a secondary mineral that forms in igneous rocks. Haematite is an important raw material for iron smelting. Ores with bright colours can become good ornamental stones.