Magnetite
Magnetite · Mineral Specimen
Crystal System
Cubic (Isometric); typically forms octahedral or dodecahedral crystals, but often appears as granular or massive aggregates.
Mineral Group
Oxides
Chemical Formula
Fe3O4
Formation Process
Igneous and metamorphic; crystallizes as an accessory mineral in most igneous rocks, as massive deposits in metamorphic iron formations, and in hydrothermal veins.
About This Crystal
The specimen is a small, dark grey to black, rough, angular rock fragment with a granular texture and a submetallic to metallic luster, typical of weathered or unpolished massive magnetite.
Physical Characteristics
Color is black to dark iron-grey with a black streak. Highly magnetic. Fracture is uneven to subconchoidal. Specific gravity is approximately 5.15. Tenacity is brittle.
Optical Properties
Opaque with a metallic to submetallic luster. Not transparent or translucent. Isotropic optically.
Hardness & Durability
Origin Region
Found globally with major deposits in Sweden, Norway, USA (Adirondacks), Russia, and South Africa. Forms in igneous rocks, metamorphic rocks, and high-temperature hydrothermal deposits.
Hardness & Durability
Mohs hardness of 5.5 to 6.5. Good durability, though heavy impacts can fracture it due to brittleness.
Care & Maintenance
Can be cleaned with warm soapy water and a soft brush. Dry thoroughly to prevent rusting of surface iron content. Store away from scratching other softer minerals.
Rarity & Value
Common mineral. Value is generally low for standard specimens, higher for well-formed octahedral crystal clusters.
Special Characteristics
Strong natural magnetism (lodestone variety exhibits permanent magnetism). High iron content.
Lore & History
Historically known as lodestone, magnetite has been used since ancient times for its magnetic properties, famously aiding in early navigation via compasses. In metaphysical lore, it is associated with grounding, alignment, and attracting positive energy.