This is not a real lodestone but an artificial one, made of 17 flat bar magnets held in a brass frame. It has a brass frame with a carrying loop on top and is 'armed' with two pieces of steel at the bottom, which help to increase the magnetic strength. There is also a steel keeper - a bar to help preserve the magnetism. It is contained in a black rayskin case. Like a real lodestone, the magnetic poles are at the sides.

Real lodestone is made of magnetite, which is naturally magnetic, and was vital in the early centuries of navigation to ensure that the ship's compass worked properly. Until the mid-18th century, when improved compasses were developed, compass needles lost their magnetism quite quickly and had to be re-magnetised by stroking a lodestone along the needle's length. It was in the 18th century that artificial lodestones like this example became more common.