28 • A Pirate's Ring of Lodestone

28 • A Pirate's Ring of Lodestone

The High Seas; Early 19th century
Bezel size: 3.2 × 2.3 cm; Lodestone, silver, steel

Named after the word lode, meaning journey or way in the Middle Ages, lodestone is one of just two naturally magnetised minerals on earth. Its importance for early navigation was immense, first used by the military of the Song dynasty of China 1,000 years ago, and picked up shortly afterwards by mariners. It was used by touching it to – and therefore magnetising – a needle of iron which was then suspended in a bowl of water to point due north. I

Its importance for sea-faring nations looking to expand their influence and trade made it a prestigious stone and extremely valuable. A display of its trickery was brilliantly captured by one spectator during a demonstration at the Royal Society in London around 1700:

It made a paper of steel filings prick up themselves one upon the back of another, that they stood pointing like the Bristles of a Hedge-Hog; and gave such Life and Merriment to a Parcel of Needles, that they danc’d…..as if the devil were in them.”

There remains great debate as to how lodestones are magnetised, though the leading theory is that they are done so by the strong magnetic fields surrounding strikes of lightening. So whereas for any seafarer who dreads lightning and the danger of an impending storm, lightening was also responsible for the magnetism in their lodestone compasses, and for guiding them safely for many hundreds of years.