mineral

Tumbled hematite-rich ironstone

Hematite (Fe₂O₃), possibly magnetite (Fe₃O₄) or iron-rich slag-like material

AI-generated identification · may be incorrect

Dark steel-gray to black, smooth and weakly metallic/submetallic luster, with rusty-brown inclusions; hematite hardness 5–6.5 Mohs, magnetite 5.5–6.5, both commonly massive rather than visibly crystalline. Hematite is nonmagnetic or weakly magnetic, while magnetite is strongly magnetic.

Identified August 23, 2026More mineral →

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Physical properties

Formation & geological history

Likely a naturally weathered or tumbled iron-oxide nodule formed by oxidation and concentration of iron in hydrothermal, sedimentary, or weathering environments; precise age and origin cannot be determined from the image.

Uses & applications

Used as iron ore, pigment, polishing material, and a lapidary/collecting stone; attractive polished pieces may be sold as hematite jewelry.

Geological facts

A strong magnet is the quickest discriminator: strong attraction suggests magnetite or maghemite, whereas little attraction favors hematite. The brown-red streak of hematite is diagnostic; magnetite produces a black streak.

Field identification & locations

Common in banded iron formations and oxidized ore zones worldwide, especially Brazil, Australia, Canada, and the United States. Test streak on unglazed porcelain and avoid assuming every black metallic stone is hematite.