Magnetite (Lodestone variety)
Magnetite (IMA listed) · Industrial Mineral and Collector Mineral
Crystal System
Cubic (Isometric); habit is typically octahedral or massive/granular as seen here
Mineral Group
Oxides (Spinel group)
Chemical Formula
Fe2+Fe3+2O4 (Iron(II,III) Oxide)
Formation Process
Igneous (magmatic segregation), metamorphic (contact and regional), and hydrothermal replacement
About This Crystal
A dense, dark brownish-black to iron-black specimen with an uneven, wet-looking surface. It exhibits a metallic to sub-metallic luster on fresh surfaces and appears opaque with a heavy, massy texture.
Physical Characteristics
Color: Iron-black to dark brown; Streak: Black; Fracture: Uneven to sub-conchoidal; Specific Gravity: 5.17; Strongly magnetic; Brittle tenacity
Optical Properties
Opaque; metallic luster; shows no pleochroism or birefringence as it is isotropic and non-transparent
Hardness & Durability
Origin Region
Global; notable sources include Kiruna (Sweden), Magnet Cove (Arkansas, USA), and the Urals (Russia)
Hardness & Durability
Mohs hardness 5.5 - 6.5; brittle toughness; stable but prone to oxidation (rusting) if kept in high humidity
Care & Maintenance
Avoid acidic cleaners; clean with a soft brush and dry immediately; store in a dry environment to prevent oxidation; keep away from electronic devices due to magnetism
Rarity & Value
Common mineral; value is generally low unless it presents as well-defined octahedral crystals or is a naturally magnetized 'Lodestone'
Special Characteristics
Strong ferrimagnetism; some specimens act as natural magnets (Lodestone); high iron content makes it noticeably heavy for its size
Lore & History
Historically used by early mariners for the first compasses (Lodestones); traditionally associated with grounding, protection, and 'attracting' goals in lore