Loadstone refers to naturally occurring pieces of intensely magnetic magnetite that were used for magnetizing compasses.

Iron, steel and ordinary magnetite are attracted to a magnetic field, including the Earth’s magnetic field. Only magnetite with a particular crystalline structure, lodestone, has the coercivity to act as a permanent magnet and attract and magnetize iron.

In China, the earliest literary reference to magnetism lies in a 4th century BCE book called Book of the Devil Valley Master “The lodestone makes iron come or it attracts it”. The earliest mention of the attraction of a needle appears in a work composed between 20 and 100 CE (Louen-heng): “A lodestone attracts a needle.”[3] By the 12th century the Chinese were known to use the lodestone compass for navigation