mineral

Magnetite (Iron Ore)

Magnetite (Fe3O4)

Hardness: 5.5-6.5 Mohs; Color: Iron-black to dark grey; Luster: Metallic to submetallic; Crystal Structure: Isometric; Cleavage: None; Specific Gravity: 5.1-5.2

Hardness: 5
Color: Iron-black to dark grey
Luster: Metallic to submetallic

Identified June 7, 2026More mineral →

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Physical properties

Hardness: 5.5-6.5 Mohs; Color: Iron-black to dark grey; Luster: Metallic to submetallic; Crystal Structure: Isometric; Cleavage: None; Specific Gravity: 5.1-5.2

Formation & geological history

Forms in igneous, metamorphic, and sedimentary environments. Often found in banded iron formations (BIFs) dating back 2-3 billion years, or as an accessory mineral in igneous rocks like basalt.

Uses & applications

Primary ore of iron for steel production; used as a heavy media for coal washing, in fertilizers, and in magnetic recording media.

Geological facts

Magnetite is the most magnetic of all the naturally-occurring minerals on Earth. Some specimens, known as lodestones, act as natural magnets and were used in the first compasses.

Field identification & locations

Identify in the field using a magnet (it will be strongly attracted) and its black streak test. Commonly found in heavy sand deposits, lode mines, and volcanic terrain.