mineral

Magnetite

Magnetite (Fe3O4)

Hardness: 5.5-6.5 on Mohs scale; Color: Black to brownish-black; Luster: Metallic to submetallic; Crystal structure: Isometric (often octahedral); Cleavage: None; Specific Gravity: 5.17-5.18

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

Identified April 1, 2026More mineral →

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Physical properties

Hardness: 5.5-6.5 on Mohs scale; Color: Black to brownish-black; Luster: Metallic to submetallic; Crystal structure: Isometric (often octahedral); Cleavage: None; Specific Gravity: 5.17-5.18

Formation & geological history

Formed primarily in igneous and metamorphic environments, often as an accessory mineral in granite, gabbro, and schist, or as a result of contact metamorphism in skarns. It can also be found in sedimentary heavy mineral sands.

Uses & applications

The most important ore of iron; used in heavy media separation, steel production, water filtration, and occasionally as a minor gemstone or for magnetic therapy studies.

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 magnetic compasses.

Field identification & locations

The easiest field identification method is its strong attraction to a magnet. It also leaves a black streak when rubbed on a porcelain plate and has a distinct high density compared to most dark minerals.