Magnetite
Oxide · Fe₃O₄
Magnetite is a black iron oxide and the most magnetic natural mineral, often forming octahedral crystals that attract a magnet.
What is magnetite?
Magnetite is an iron oxide and the most strongly magnetic mineral in nature; naturally magnetised pieces are called lodestone. It is black with a metallic sheen, forms sharp octahedral crystals and heavy granular masses, and is a valuable iron ore.
Properties
- Chemical formula
- Fe₃O₄
- Category
- Oxide
- Hardness (Mohs)
- 5.5–6.5
- Crystal system
- Cubic (isometric)
- Lustre
- Metallic
- Streak
- Black
- Colour
- Black
- Cleavage / fracture
- None
How to identify magnetite
- →Attracts a magnet strongly (the defining test).
- →Black colour with a black streak.
- →Often octahedral crystals; heavy.
- →Hardness 5.5–6.5.
Where magnetite is found
Magnetite is worldwide, with fine crystals from the Alps, Sweden (Kiruna) and the USA.
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