Magnetite (Fe₃O₄) is the strongly magnetic iron oxide and one of the principal iron ores. Its octahedral crystal habit and natural magnetism (lodestone variety) make it instantly recognizable. Magnetite forms in mafic-ultramafic igneous rocks, banded iron formations, and contact-metamorphic skarns. Anshan (Liaoning) and Panzhihua (Sichuan) are major Chinese ore producers.
Key Facts
- Mohs hardness 5.5–6.5.
- Isometric; classic octahedral and dodecahedral crystals.
- Strongly magnetic — naturally occurring lodestone is the most magnetic mineral.
- Black streak distinguishes from hematite (red streak).
- Major iron ore in BIF and contact metamorphic skarn deposits.
Notable Localities
Anshan (Liaoning) and Panzhihua (Sichuan) host massive Chinese ore. Cerro de Mercado (Mexico) yields gem-grade octahedrons. Faraday Mine (Ontario) supplies large crystals.
Found at these Localities
- Kola Peninsula Alkaline Complexes (科拉半岛碱性杂岩)
- Tunaberg (图纳贝里钴矿(瑞典))
- Trimouns Talc Mine (特里穆滑石矿(法国))
- Magnet Cove (马格尼特湾碱性杂岩)
- Cida (Hongge) V-Ti-Fe Deposit ((红格)钒钛铁矿)
- Panzhihua V-Ti-Magnetite Mine (攀枝花钒钛磁铁矿)
- Sichuan (四川)
