mineral

Magnetite (Iron Ore)

Magnetite (Fe3O4)

Hardness: 5.5-6.5; Color: Black to brownish-black; Luster: Metallic to submetallic; Crystal structure: Isometric (octahedral); Cleavage: None; Specific gravity: 5.1-5.2

Hardness: 5
Color: Black to brownish-black
Luster: Metallic to submetallic

Identified April 9, 2026More mineral →

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Physical properties

Hardness: 5.5-6.5; Color: Black to brownish-black; Luster: Metallic to submetallic; Crystal structure: Isometric (octahedral); Cleavage: None; Specific gravity: 5.1-5.2

Formation & geological history

Formed in igneous, metamorphic, and sedimentary environments. Often found as an accessory mineral in igneous rocks or as a result of contact metamorphism in limestone. Can also be found as large ore bodies.

Uses & applications

Primary ore of iron; used in heavy media separation, steel production, and as an industrial abrasive. Occasionally used as a gemstone in magnetic jewelry.

Geological facts

Magnetite is the most magnetic of all the naturally-occurring minerals on Earth. Pieces of magnetite that act as natural magnets are called lodestones, which were used by ancient civilizations for early navigation.

Field identification & locations

Identify in the field by its black streak on a porcelain plate and its strong attraction to hand magnets. High density/weight is also a key indicator. Commonly found in locations like the Adirondack Mountains, Sweden, and South Africa.