Incised gemstones or intaglios (in Italian, glittica) were produced in Etruria from about 540 BC. They were preceded by faience scarabs of Egyptian or Egyptianizing origin in the eighth and seventh centuries BC and ivory and bone seals with an incised base in the first half of the sixth century BC. Intaglios were popular in the coastal cities of Etruria and usually depicted a divinity or a hero (Aivas, Achle, etc.), accompanied by an inscription of the name, used as a seal and inserted in a ring. Gemstones continued to be produced until the last centuries BC, moving from a severe to a more free style. Incised gemstones were often collected in the eighteenth century and therefore many lack provenance.
Historical Dictionary of the Etruscans. Simon K. F. Stoddart.