mineral

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 (Octahedral), Cleavage: None (has parting), Specific Gravity: 5.1-5.2

Hardness: 5

Identified June 3, 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 (Octahedral), Cleavage: None (has parting), Specific Gravity: 5.1-5.2

Formation & geological history

Typically forms in igneous rocks like basalt and gabbro through magmatic segregation, or in metamorphic rocks like gneiss and schist. It can also be found in sedimentary banded iron formations.

Uses & applications

The primary ore of iron for steel manufacturing; used in heavy media separation, as a toner in photocopiers, and as a micronutrient in fertilizers. High-quality specimens are popular for collectors.

Geological facts

Magnetite is the most magnetic of all the naturally occurring minerals on Earth. Naturally magnetized pieces called lodestones were used to create the first compasses in history.

Field identification & locations

The easiest field identification is its strong attraction to a magnet. It also produces a black streak when rubbed on a porcelain plate and has a distinct high density (feels heavy for its size).