Magnetite (Lodestone)
Magnetite (Iron Oxide) · Collector Mineral and Industrial Ore
Crystal System
Cubic (Isometric); habit is typically octahedral, dodecahedral, or massive/granular
Mineral Group
Oxides (Spinel Group)
Chemical Formula
Fe2+Fe3+2O4
Formation Process
Igneous (magmatic segregation), Metamorphic (contact/regional), and Hydrothermal veins
About This Crystal
Dark grey to black metallic mineral with a sub-metallic to metallic luster. Occurs in heavy, dense masses with a rugged, uneven surface and characteristic granular texture.
Physical Characteristics
Color: Iron-black; Streak: Black; Cleavage: None (parting on {111}); Fracture: Uneven to sub-conchoidal; Specific Gravity: 5.17-5.18; Strongly magnetic.
Optical Properties
Opaque; metallic luster; shows occasional reddish tint in reflected light (under microscopy). Non-pleochroic.
Hardness & Durability
Origin Region
Kiruna (Sweden), Barberton (South Africa), Adirondacks (USA), and various Banded Iron Formations
Hardness & Durability
Mohs hardness: 5.5 - 6.5. Brittle tenacity; stable under normal conditions but can oxidize to hematite (martite).
Care & Maintenance
Store in a dry environment to prevent rusting. Keep away from electronic devices and credit cards due to strong magnetism (if lodestone). Clean with a soft dry cloth.
Rarity & Value
Very common as an iron ore; high-quality octahedral crystals or naturally magnetized lodestones are preferred by collectors.
Special Characteristics
Strongly ferrimagnetic; lodestone varieties act as natural magnets. High iron content makes it noticeably heavy (high specific gravity).
Lore & History
Used by ancient Greek and Chinese sailors as the first compasses. Historically associated with 'attraction' and grounding in various cultural folk traditions.