mineral

Magnetite or Magnetic Iron Ore

Magnetite (Fe3O4)

Hardness: 5.5-6.5 on Mohs scale; Color: Black, brownish-black; Luster: Metallic to sub-metallic; Crystal structure: Isometric (octahedron); Cleavage: None (parting may be present); Specific gravity: 5.1-5.2

Hardness: 5
Color: Black, brownish-black
Luster: Metallic to sub-metallic

Identified June 26, 2026More mineral →

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Physical properties

Formation & geological history

Commonly formed in igneous rocks as an accessory mineral or in metamorphic rocks through regional metamorphism. It can also occur in sedimentary rocks as heavy mineral sands. It is found in deposits dating back to the Precambrian era.

Uses & applications

Major ore of iron for steel manufacturing; used in industrial catalysts, magnetic recording media, pigments, and as a heavy aggregate in construction. High-quality specimens are valued by mineral collectors.

Geological facts

Magnetite is the most magnetic of all the naturally-occurring minerals on Earth. Some varieties, known as lodestones, act as natural magnets and were used by early sailors as a primitive compass.

Field identification & locations

Identify in the field using a handheld magnet (it is strongly attracted). It leaves a black streak on a porcelain plate and has a high density/weight for its size. Common in mining districts like Kiruna, Sweden, and various locations in North America and Russia.