This is a cameo made in Rome around 1800 and signed Mango. The cameo is oval, carved in onyx with the Genius of Rome.

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.
Many gems were carved in the neo-classical style popular in the late 1700s and early 1800s, when taste in the arts echoed the subject matter and style of the Greek and Roman masters. Thousands of gems were made in this style in Italy and brought back by British Grand Tourists, who went there to visit the newly-discovered classical antiquities and archaeological sites.