mineral

Hematite Nodular Concretion

Iron(III) oxide (Fe2O3)

Hardness: 5.5-6.5; Color: Steel-gray to black with a dull to metallic luster; Crystal Structure: Trigonal (rhombohedral); Specific Gravity: 5.26; Reddish-brown streak.

Hardness: 5
Color: Steel-gray to black with a dull to metallic luster

Identified June 12, 2026More mineral →

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Physical properties

Hardness: 5.5-6.5; Color: Steel-gray to black with a dull to metallic luster; Crystal Structure: Trigonal (rhombohedral); Specific Gravity: 5.26; Reddish-brown streak.

Formation & geological history

Formed via precipitation from iron-rich water in sedimentary environments, often congregating around a core to form a nodule. These can date back billions of years in Banded Iron Formations.

Uses & applications

Primary ore for iron and steel production; also used as a gemstone, for pigments (red ochre), and in radiation shielding.

Geological facts

Hematite is found on Mars (Martian 'blueberries' are tiny hematite spherules) and it gets its name from the Greek word 'haima' meaning blood, due to the color of its streak.

Field identification & locations

Identify in the field by its high density and characteristic reddish-brown streak when scratched against a porcelain plate. Common in sedimentary basins worldwide.