mineral
Magnetite (Iron Ore)
Magnetite (Fe3O4)
AI-generated identification · may be incorrectHardness: 5.5-6.5; Color: Iron-black to dark gray; Luster: Metallic to submetallic; Crystal structure: Isometric; Streak: Black; Specific Gravity: 5.1-5.2; Highly magnetic.
- Hardness
- 5
- Color
- Iron-black to dark gray
- Luster
- Metallic to submetallic
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Physical properties
Hardness: 5.5-6.5; Color: Iron-black to dark gray; Luster: Metallic to submetallic; Crystal structure: Isometric; Streak: Black; Specific Gravity: 5.1-5.2; Highly magnetic.
Formation & geological history
Typically found as an accessory mineral in igneous rocks (gabbro, basalt, granite), in metamorphic rocks, and as a major component of Banded Iron Formations (BIFs) formed by precipitation in ancient oxygenating oceans over 2 billion years ago.
Uses & applications
The most important ore of iron for the production of steel; used as a heavy media for coal washing, in magnetic inks, and as an industrial toner.
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 early compasses.
Field identification & locations
Identify in the field by its strong attraction to magnets, black streak, and high density. It is commonly found in heavy mineral sands or as veins in metamorphic terrains.
