Opus sectile

Images or patterns composed of individually shaped pieces of durable material, usually stone or glass, where each piece forms an element in the design or pattern. It is distinguished from mosaics, which use small fragments of stone or glass (tesserae) to fill in areas or lines in the design, but each tessera does not itself form a pattern or element. Opus sectile originated in Egypt and Asia Minor. It was considered a rarer and more luxurious art than straightforward mosaic. Little survives before Roman times; it was later used in Early Christian and Byzantine churches, and remained popular in Italy, particularly in church floors, throughout the Middle Ages and Renaissance.