Chemical Composition
Formula: Fe₃O₄ (Iron oxide)
Physical Properties
Color: Black, grayish black
Luster: Metallic
Hardness (Mohs Scale): 5.5 – 6.5
Density: 5.17 – 5.18 g/cm³
Cleavage: None
Fracture: Irregular to conchoidal
Magnetism: Strongly magnetic (the most magnetic natural mineral)
Origin and Location
Origin: Mainly forms in igneous, metamorphic, and sedimentary rocks.
Major Deposits:
United States (Minnesota, Michigan)
Sweden (Kiruna)
Russia (Ural Mountains)
Italy (Elba)
South Africa
Varieties
Titanomagnetite: Magnetite rich in titanium
Maghemite: Partially oxidized magnetite, forming hematite
Uses and Applications
Steel Industry: Main source of iron for steel production
Electronics: Used in magnetic tapes and data storage
Medicine: Used in nanoparticles for MRI (Magnetic Resonance Imaging)
Curiosities or Interesting Facts
Used by the Chinese as early as the 4th century BC to make the first compasses.
Migratory birds use magnetite in their tissues to navigate Earth's magnetic fields.
Magnetite is one of the few minerals that can be attracted to a magnet and can also become a natural magnet itself.
Formation Process
Magmatic: Crystallizes from iron-rich magma.
Metamorphic: Recrystallization under high pressure and temperature.
Sedimentary: Chemical deposits in iron-rich marine or lacustrine environments.
History and Discovery
Discovery: Known since antiquity; used by Greeks and Chinese for its magnetic properties.
Name Origin: Derived from the region of Magnesia (Greece), where it was first found.
Optical Properties
Microscope Color: Opaque but reflects light with a metallic sheen.
Pleochroism: Absent
Mineral Classification
Class: Oxides
Group: Spinel