mineral

Magnetite

Magnetite (Fe3O4)

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

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

Identified July 21, 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 (Octahedral); Cleavage: None (parting); Specific Gravity: 5.1-5.2

Formation & geological history

Forms in igneous rocks through magmatic segregation, in metamorphic rocks like marble and greenstone, and as heavy sand in sedimentary environments. Common in banded iron formations.

Uses & applications

Major ore of iron for steel production. Used in water purification, industrial pigments, and as a component in heavy concrete for radiation shielding.

Geological facts

It is the most magnetic of all naturally occurring minerals on Earth. Naturally magnetized pieces called lodestones were used to create the earliest compasses.

Field identification & locations

Identify using a magnet; it is strongly attracted and can even be naturally magnetic. Found worldwide in iron-rich geological regions. Collectors look for well-defined octahedral crystals.