Pebble mosaic, type of mosaic work that uses natural pebbles arranged to form decorative or pictorial patterns. It was used only for pavements and was the earliest type of mosaic in all areas of the eastern Mediterranean, appearing in Asia Minor in excavated floors from the 8th and 7th centuries bc. The first pebble mosaics had rough geometric designs, but artists in Greece by the 5th century bc had achieved a degree of technical proficiency that allowed them to create designs and figures with delicacy and considerable detail, as in a series of black-and-white mosaic floors depicting mythological scenes at Olynthus in northern Greece (c. 400 bc).
Most pebble mosaics were made simply with dark and light patterns, but a few were multicoloured, such as the magnificent floors from the late 4th century bc found at Pella in Macedonia, which show monumental figures of people and animals rendered with impressive naturalism and grace. Pebble mosaics persisted as the major form of mosaic decoration until approximately the 3rd century bc, when they began to be replaced with mosaics of cut stone cubes, or tesserae. The later pebble mosaics, including those at Pella, were increasingly supplemented with stone tesserae chosen for colour intensity and with lead or terra-cotta strips for delineation of detail.