mineral

Magnetite (Lodestone)

Magnetite (Fe3O4)

Hardness: 5.5-6.5; Color: Iron-black to silvery-gray; Luster: Metallic to submetallic; Crystal Structure: Isometric; Cleavage: None; Specific Gravity: 5.1-5.2

Hardness: 5
Color: Iron-black to silvery-gray
Luster: Metallic to submetallic

Identified July 21, 2026More mineral →

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Physical properties

Hardness: 5.5-6.5; Color: Iron-black to silvery-gray; Luster: Metallic to submetallic; Crystal Structure: Isometric; Cleavage: None; Specific Gravity: 5.1-5.2

Formation & geological history

Formed in igneous, metamorphic, and sedimentary environments through various processes, often as a result of magmatic differentiation in mafic or ultramafic melts, or in hydrothermal veins and contact metamorphism.

Uses & applications

Primary ore of iron; used as a heavy media in coal washing, as a pigment in paints and plastics, and in industrial filtration; also used in magnetic recording systems and as a gemstone/mineral specimen.

Geological facts

Magnetite is the most magnetic of all the naturally occurring minerals on Earth. Some specimens, known as lodestones, are naturally magnetized and were used by early mariners as primitive compasses.

Field identification & locations

Identified by its strong magnetism (it will attract a magnet), black streak on a porcelain plate, and heavy weight for its size. Common in Canada, Sweden, USA (New York, Pennsylvania), South Africa, and Russia.