The Turkish "boncuk" (sometimes called a "göz boncuğu" 'eye bead') is a glass bead characterized by a blue glass field with a blue or black dot superimposed on a white or yellow center. Historically old, the blue bead has gained importance as an item of popular culture in Modern Turkey. The bead probably originated in the Mediterranean and is associated with the development of glass making. Written documents and extant beads date as early as the 16th century BC. Glass beads were made and widely used throughout the ancient world: from Mesopotamia to Egypt, from Carthage and Phoenicia to Persia, and throughout the Roman imperial period.