mineral

Magnetite (Iron Ore)

Magnetite (Fe3O4)

Hardness: 5.5-6.5; Color: Black to dark gray; Luster: Metallic to submetallic; Crystal Structure: Isometric (octahedral); Cleavage: None; Specific Gravity: 5.1-5.2; Strongly magnetic.

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

Identified July 6, 2026More mineral →

Explore Magnetite (Iron Ore) in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Hardness: 5.5-6.5; Color: Black to dark gray; Luster: Metallic to submetallic; Crystal Structure: Isometric (octahedral); Cleavage: None; Specific Gravity: 5.1-5.2; Strongly magnetic.

Formation & geological history

Formed in igneous, metamorphic, and sedimentary environments. Commonly occurs as an accessory mineral in igneous rocks like granite and basalt, or in banded iron formations (BIFs).

Uses & applications

Primary ore of iron for steel production; used as a heavy media for coal separation; abrasive; and in the manufacturing of toners and pigments.

Geological facts

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

Field identification & locations

Identify in the field using a magnet; it is one of the few minerals strongly attracted to them. Found worldwide, notably in Sweden, Brazil, and the USA (Great Lakes region). Look for high density and black streak.