A lodestone is formed from the mineral magnetite that has become naturally magnetic over time. No one knows exactly how the magnetism happens but one theory is that bolts of lightning striking the magnetite causes the magnetic domains in the rock to become aligned. Anciently lodestone was used for navigation and for medicine. The first compass was made with a lodestone! These lodestones are not heavy-duty magnets. They are lightly magnetic and will attract small metallic objects like staples, paperclips and iron filings. The iron ore content also make the lodestones attracted to other magnets.