mineral

Magnetite

Magnetite (Fe3O4)

Hardness: 5.5-6.5; Color: Black to silvery gray; Luster: Metallic to submetallic; Crystal Structure: Isometric; Cleavage: None (parting sometimes observed); Specific Gravity: 5.1-5.2

Hardness: 5
Color: Black to silvery gray
Luster: Metallic to submetallic

Identified June 29, 2026More mineral →

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Physical properties

Hardness: 5.5-6.5; Color: Black to silvery gray; Luster: Metallic to submetallic; Crystal Structure: Isometric; Cleavage: None (parting sometimes observed); Specific Gravity: 5.1-5.2

Formation & geological history

Formed in igneous, metamorphic, and sedimentary environments. Often occurs as an accessory mineral in igneous rocks like basalt and gabbro, or in banded iron formations. Can also form through hydrothermal processes.

Uses & applications

The most important ore of iron for the steel industry. Also used in scientific research (biomagnetism), as a heavy medium for coal washing, and as a pigment. High-quality crystals are valued by mineral collectors.

Geological facts

Magnetite is the most magnetic of all naturally occurring minerals on Earth. Naturally magnetized pieces called lodestones were used to create the first compasses. Some animals, including birds and bees, contain magnetite in their bodies to help them navigate using Earth's magnetic field.

Field identification & locations

Identified in the field by its black color, black streak, and strong attraction to a magnet. It is commonly found in beach sands (as 'black sand') or in massive beds. Collectors look for well-formed octahedral crystals.