Magnetite
ID: 29
Magnetite
Chemical Formula
Fe₃O₄
Hardness (Mohs)
5.5 - 6.5
Crystal System
Isometric
Streak
Black
Luster
Metallic to submetallic
Diaphaneity
Opaque
Color
Iron-black
Crystal Habit / Mode of Occurrence
Isometric - Hexoctahedral; commonly in octahedral crystals, sometimes dodecahedral or cubic; also massive, granular, or compact.
Fun Facts
Magnetite is the most magnetic mineral found on Earth, and naturally magnetized pieces are known as "lodestone," which were used in early compasses. Common Uses: Important ore of iron, used in high-density aggregate, historical use as lodestone (natural magnet), magnetic recording.