Circa 300-400 AD. Medusa head (gorgoneion) with wings in the wild hair and snakes around the face. This was used in the late Roman period, presumably offering demonic protection for the wearer in the way the same subject does on a shield or aegis. The back is rough and broken having been cobbed out of the stone with a hammer. The head of Medusa, also known as the gorgoneion, was perhaps "the most ubiquitous subject employed for cameos" during the Roman Period (p. 183 in M. Henig and H. Molesworth, The Complete Content Cameos). When used in jewellery it was thought to have amuletic or apotropaic properties, conferring protection to the wearer, including from the Evil Eye. The subject was popular already in the Archaic period in Greece when she was depicted as a ferocious monster. By the Hellenistic period, the image became more humanized. During the Roman period, the type is typically shown either frontally or slightly turned, as here, with wings in her hair, the face framed by serpents. The most common materials were sardonyx, chalcedony, carnelian, or glass imitating them. The present example is considerably larger than most, and by far one of the finest in existence. It was mounted as a pendant in a gold frame, most likely in the 18th century.Size: L:28mm / W:28mm ; 10gProvenance: Central London private collection of Ancient Art and jewellery; acquired from an East Coast, US estate collection formed before 1979.