Hematite: Properties, Uses, and Geologic Formation

Hematite (Fe₂O₃) is the most abundant iron oxide mineral and primary ore of iron.

Physical Properties

• Color: Steel-gray to black (specular); red-brown (earthy); streak always cherry-red.
• Luster: Metallic to dull.
• Hardness: 5.5–6.5 Mohs.
• Specific gravity: 5.26 (heavy).
• Magnetism: Weakly ferromagnetic; attracted to strong magnets when pure.
• Crystal system: Trigonal (rhombohedral).

Formation

• Sedimentary: Banded iron formations (BIFs) – Precambrian oceans.
• Hydrothermal: Vein deposits.
• Weathering: Oxidation of magnetite, pyrite, siderite → secondary hematite (gossan).
• Direct precipitation: From iron-rich waters (hot springs, lakes).

Uses

• Iron/steel production (90%+ of consumption).
• Pigment: Red ochre, Venetian red, paint, cosmetics, ceramics.
• Jewelry: Cabochons, beads (hematine = synthetic simulant).
• Heavy media separation, radiation shielding, catalysts.