mineral

Magnetite

Magnetite (Iron(II,III) oxide, Fe3O4)

Hardness: 5.5-6.5 Mohs, Color: Iron-black to dark grey, Luster: Metallic to submetallic, Crystal Structure: Isometric (often octahedral), Cleavage: None (has parting), Specific Gravity: 5.1-5.2

Hardness: 5

Identified May 26, 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 (often octahedral), Cleavage: None (has parting), Specific Gravity: 5.1-5.2

Formation & geological history

Commonly forms in igneous rocks like basalt and gabbro through magmatic segregation, in metamorphic rocks through regional metamorphism, and in sedimentary environments as a heavy mineral sand.

Uses & applications

Primary ore of iron; used in heavy media separation, as a pigment (mars black), as an abrasive, and in magnetic recording media.

Geological facts

Magnetite is the most magnetic of all the naturally occurring minerals on Earth. Naturally magnetized pieces are called lodestones and were used as the first primitive compasses.