mineral
Magnetite (Loadstone candidate)
Iron(II,III) oxide (Fe3O4)
Hardness: 5.5-6.5; Color: Black to dark gray; Luster: Metallic to submetallic; Crystal Structure: Isometric/Octahedral; Cleavage: None; Specific Gravity: 5.17-5.18; Magnetic: Strongly magnetic.
- Hardness
- 5
- Color
- Black to dark gray
- Luster
- Metallic to submetallic
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Physical properties
Hardness: 5.5-6.5; Color: Black to dark gray; Luster: Metallic to submetallic; Crystal Structure: Isometric/Octahedral; Cleavage: None; Specific Gravity: 5.17-5.18; Magnetic: Strongly magnetic.
Formation & geological history
Formed in igneous, metamorphic, and sedimentary rocks through crystallization from a melt or precipitation from hydrothermal fluids. Common in banded iron formations and as heavy mineral sand.
Uses & applications
Primary ore of iron; used in heavy media separation, as a pigment (mars black), and historically as early compasses (lodestone).
Geological facts
Magnetite is the most magnetic of all the naturally-occurring minerals on Earth. It was used by ancient civilizations to create the first navigational compasses.
Field identification & locations
Identify in the field by its black streak, high density, and strong attraction to a magnet. Look for it in dark, heavy sands or as inclusions in igneous rocks like basalt.
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