mineral
Magnetite (potentially Lodestone)
Magnetite (Iron(II,III) oxide, Fe3O4)
Hardness: 5.5-6.5; Color: Black or dark grey; Luster: Metallic to submetallic; Crystal structure: Isometric (octahedron); Streak: Black; Magnetic: Strongly magnetic.
- Hardness
- 5
- Color
- Black or dark grey
- Luster
- Metallic to submetallic
Identified More mineral →
Explore Magnetite (potentially Lodestone) in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 5.5-6.5; Color: Black or dark grey; Luster: Metallic to submetallic; Crystal structure: Isometric (octahedron); Streak: Black; Magnetic: Strongly magnetic.
Formation & geological history
Common in igneous rocks such as basalt and gabbro, as well as metamorphic rocks and some sedimentary deposits. It forms through crystallization from silica-rich magmas or by hydrothermal processes.
Uses & applications
The main ore of iron. Used in steel production, as a magnet in compasses historically, and as a heavy medium for coal separation.
Geological facts
Magnetite is the most magnetic of all the naturally-occurring minerals on Earth. Naturally magnetized pieces called lodestone were the first magnetic compasses used by humans.
Field identification & locations
Can be identified in the field using a handheld magnet or by its black streak. Often found in heavy mineral sands or as small grainy crystals in darker volcanic stones.
More like this
Other mineral specimens
Sandstone (with potential mineral staining/concretions)
Arenite (SiO2 based)
sedimentary
Sandstone with Mineral Veining or Crust
Sedimentary Sandstone (mostly SiO2 with Fe2O3 tinting)
sedimentary
Schist
Schist
Metamorphic
Potassium Feldspar (Orthoclase)
Orthoclase (KAlSi3O8)
mineral
Gypsum (variety Selenite or Alabaster)
Calcium sulfate dihydrate (CaSO4·2H2O)
Mineral
Nephrite Jade
Nephrite
Mineral/Rock