Magnetite with Goethite and Hematite
Magnetite (Fe3O4) · Mineral Specimen / Industrial Ore
Crystal System
Cubic (Isometric); typically octahedral crystals or massive/granular habit as seen here.
Mineral Group
Oxides (Spinel Group)
Chemical Formula
Fe2+Fe3+2O4 (often with trace TiO2 or MnO)
Formation Process
Igneous (magmatic segregation) or Metamorphic (regional or contact), also found in hydrothermal veins.
About This Crystal
Dark grey to black metallic mineral with a granular to sub-metallic luster. Shows visible surface oxidation (brownish goethite) and a high-density, rugged texture with micro-crystalline clusters.
Physical Characteristics
Color: Iron-black; Streak: Black; Cleavage: None (parting on {111}); Fracture: Subconchoidal to uneven; Specific Gravity: 5.1-5.2; Strongly magnetic.
Optical Properties
Opaque; metallic luster; isotropic in reflected light; no pleochroism or birefringence.
Hardness & Durability
Origin Region
Common worldwide; notable specimens from Iron Mountain, USA; Kiruna, Sweden; and various Brazil locations.
Hardness & Durability
Mohs Hardness: 5.5 - 6.5; Brittle tenacity; stable under normal conditions but prone to oxidation (rusting).
Care & Maintenance
Keep dry to prevent further oxidation; clean with soft brush and dry cloth; avoid acids which can dissolve iron oxides; store away from other sensitive magnets.
Rarity & Value
Common mineral; value for specimens depends on crystal perfection (e.g., sharp octahedrons) or unique locale; industrial value as iron ore is high but specimen price is low.
Special Characteristics
Strong ferrimagnetism; may exhibit polarity (Lodestone); occasionally forms pseudomorphs after other minerals.
Lore & History
Used by ancient navigators in the form of Lodestone for early compasses. Historically associated with grounding and attraction in various cultural lore.