mineral

Magnetite (or Magnetic Iron Ore)

Magnetite (Fe3O4)

Hardness: 5.5-6.5; Color: Black to brownish-black; Luster: Metallic to submetallic; Crystal Structure: Isometric (often octahedral); Cleavage: None (has parting); Specific gravity: 5.1-5.2; Highly magnetic.

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

Identified June 27, 2026More mineral →

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Physical properties

Formation & geological history

Typically forms in igneous and metamorphic rocks through magmatic segregation or hydrothermal replacement. It is often found in contact metamorphic zones where iron-rich fluids react with carbonate rocks.

Uses & applications

The primary ore of iron for steel manufacturing; used as a heavy media for coal separation, in industrial toners, and as a component in high-density concrete.

Geological facts

Magnetite is the most magnetic of all naturally occurring minerals on Earth. Naturally magnetized pieces called 'lodestones' were the first primitive magnetic compasses used in ancient navigation.

Field identification & locations

Identify by its strong attraction to magnets, black streak on a porcelain plate, and high density. It is commonly found in beach sands as 'black sand' or within igneous rocks like basalt and granite.