mineral

Magnetite

Magnetite (Fe3O4)

AI-generated identification · may be incorrect

Hardness: 5.5-6.5 Mohs. Color: Black to brownish-black. Luster: Metallic to submetallic. Crystal structure: Isometric (octahedral). Cleavage: None. Specific Gravity: 5.1-5.2. Strongly magnetic.

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

Identified July 4, 2026More mineral →

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Physical properties

Hardness: 5.5-6.5 Mohs. Color: Black to brownish-black. Luster: Metallic to submetallic. Crystal structure: Isometric (octahedral). Cleavage: None. Specific Gravity: 5.1-5.2. Strongly magnetic.

Formation & geological history

Formed in igneous, metamorphic, and sedimentary environments. Typically found in granite pegmatites, contact metamorphic rocks, and as detrital grains in beach sands. Can be billions of years old.

Uses & applications

Primary ore of iron. Used in steel production, as a heavy media for coal separation, in toners for laser printers, and as a pigment. Collected for its magnetic properties.

Geological facts

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

Field identification & locations

Identified in the field by its black streak, high density, and strong attraction to a magnet. Commonly found in heavy mineral sands and as accessory minerals in dark igneous rocks like basalt.