The magnetic compass is an old Chinese invention, probably first made in China during the Qin dynasty (221-206 B.C.) Lodestones (a mineral composed of an iron oxide which aligns itself in a north-south direction) turned out to be better at pointing out real directions, leading to the first compasses. They designed the compass on a square slab which had markings for the cardinal points and the constellations. The pointing needle was a lodestone spoon-shaped device, with a handle that would always point south. Magnetized needles used as direction pointers instead of the spoon-shaped lodestones appeared in the 8th century AD, again in China, and between 850 and 1050 they seem to have become common as navigational devices on ships.