mineral

Magnetite (Iron Ore)

Magnetite (Fe3O4)

AI-generated identification · may be incorrect

Hardness: 5.5-6.5; Color: Iron-black to dark gray; Luster: Metallic to submetallic; Crystal structure: Isometric; Streak: Black; Specific Gravity: 5.1-5.2; Highly magnetic.

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

Identified July 17, 2026More mineral →

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Physical properties

Hardness: 5.5-6.5; Color: Iron-black to dark gray; Luster: Metallic to submetallic; Crystal structure: Isometric; Streak: Black; Specific Gravity: 5.1-5.2; Highly magnetic.

Formation & geological history

Typically found as an accessory mineral in igneous rocks (gabbro, basalt, granite), in metamorphic rocks, and as a major component of Banded Iron Formations (BIFs) formed by precipitation in ancient oxygenating oceans over 2 billion years ago.

Uses & applications

The most important ore of iron for the production of steel; used as a heavy media for coal washing, in magnetic inks, and as an industrial toner.

Geological facts

Magnetite is the most magnetic of all the naturally-occurring minerals on Earth. Naturally magnetized pieces called lodestones were used by ancient mariners as early compasses.

Field identification & locations

Identify in the field by its strong attraction to magnets, black streak, and high density. It is commonly found in heavy mineral sands or as veins in metamorphic terrains.