mineral

Magnetite-rich ironstone (probable magnetite ore)

Magnetite, Fe₃O₄, likely in a fine-grained ironstone matrix

AI-generated identification · may be incorrect

Dark gray to black, metallic-to-submetallic luster, massive and granular; magnetite has Mohs hardness 5.5–6.5, no cleavage, and specific gravity about 5.2. The specimen appears weathered, with rusty brown oxidation patches and a strongly magnetic nature expected.

Identified August 11, 2026More mineral →

Explore Magnetite-rich ironstone (probable magnetite ore) in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Formed through igneous, metamorphic, or sedimentary iron-enrichment processes; magnetite commonly crystallized during Precambrian banded-iron formation or hydrothermal/metamorphic alteration. Exact age and setting cannot be determined from the photograph.

Uses & applications

Used as iron ore, dense aggregate, radiation shielding, and pigment; attractive crystalline specimens are collected but this rough piece has limited gem or ornamental use.

Geological facts

Magnetite is the naturally magnetic iron oxide responsible for lodestone. Weathering commonly converts its surface to reddish-brown hematite or goethite.

Field identification & locations

Test with a strong magnet, which should attract it; streak is black, and its high density is notable. Common sources include banded-iron formations, skarns, mafic igneous rocks, and placer deposits worldwide.