Lodestone
Variety Fe3O4
Also called Loadstone
About it
Magnetite that is itself a natural magnet: it picks up iron filings and pins, not just clings to a magnet. Used for the first compasses; Magnet Cove, Arkansas, is a known source.
- Type
- Variety
- Group
- Magnetite variety
- Formula
- Fe3O4
- Hardness (Mohs)
- 5.5–6.5
- Specific gravity
- 5.17–5.18
- Streak
- black
- Lustre
- metallic, submetallic
- Crystal system
- Isometric (cubic)
- Colours
- black, dark grey
- Transparency
- opaque
- Cleavage and fracture
- none; octahedral parting, uneven fracture
- Magnetic
- Strongly
Typical values: real specimens vary. For more, see mindat.org.