mineral

Magnetite / Iron Ore

Magnetite (Fe3O4)

Hardness: 5.5-6.5 on Mohs scale; Color: Black to brownish-black; Luster: Metallic to submetallic; Crystal structure: Isometric (often octahedral); Specific gravity: 5.1-5.2; Streak: Black

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

Identified April 7, 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); Specific gravity: 5.1-5.2; Streak: Black

Formation & geological history

Primary mineral in igneous rocks like gabbro or granite; also forms through contact metamorphism in skarns and often precipitates in sedimentary banded iron formations (BIFs).

Uses & applications

Primary ore of iron used for steel production; also used as an abrasive, a black pigment in paints, and in magnetic separation processes.

Geological facts

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

Field identification & locations

Identify in the field using a handheld magnet (it will be strongly attracted) and its notable density. Found in major deposits in Sweden (Kiruna), Australia, Brazil, and the USA (Mesabi Range).