This is a Graeco-Roman statuette in chalcedony set on a pedstal of red carnelian. This statuette represents Dioscurus in miniature size.
The art of engraving gemstones can be traced back to ancient Greece in the 8th century BC and earlier. Techniques passed down to the Egyptians and then to the Romans. There were major revivals of interest in engraved gems in Europe during the Byzantine era, the Middle Ages, the Renaissance, and again in the 18th and 19th centuries. At each stage cameos and intaglios, these skillful carvings on a minute scale, were much prized and collected, sometimes as symbols of power mounted in jewelled settings, sometimes as small objects for private devotion or enjoyment.