Brass mounted lodestone, France 18th century.

A brass mounted lodestone.
French, 18th century.

Measures 6 x 5.5 x 2.9cm excluding loose bail.
Weighs 254.8 grams.

A lodestone is a naturally occurring, magnetized mineral composed of magnetite (Fe?O?). It is unique because it exhibits natural magnetism, which allows it to attract iron and other ferromagnetic materials. Lodestones were used to re-magnetise compass needles, which gradually lost their magnetism over time and prevented the compass from functioning correctly.