Hematite

Physical Properties

Hardness: 5.5–6.5 Mohs scale. Color: Steel-gray to black in crystals, dull red in earthy varieties. Luster: Metallic to sub-metallic. Crystal Structure: Hexagonal (rhombohedral). Cleavage: None. Specific Gravity: 5.26.

Formation & Geological History

Formed in sedimentary environments via precipitation from water, or as a sublimation product in volcanic areas. It is found in Banded Iron Formations (BIFs) dating back over 2 billion years (Precambrian), though it can form in any age.

Uses & Applications

Primary ore of iron for steel production. Also used as a polishing abrasive (jeweler's rouge), pigment (ochre), and in jewelry as beads or carved 'black diamond' substitutes.

Geological Facts

Hematite always leaves a rust-red streak when rubbed on a porcelain plate, even if the specimen looks metallic black. It is the mineral responsible for the reddish color of the planet Mars.

Field Identification & Locations

Identify in the field by its high density (feels heavy for its size) and its characteristic red streak. Commonly found in Brazil, Australia, and the Lake Superior region of North America. Often found associated with magnetite and quartz.

Identified on: 3/13/2026

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