oval, the aventurine plaque inlaid with St Peter's Square in Rome, within a 9ct gold mount, repairs, width approximately 33mm; a micromosaic brooch, 19th century, circular, the plaque inlaid with the Doge's Palace in Venice, within an aventurine border, backed by a metal frame, diameter approximately 33mm; and a micromosaic plaque, 19th century, oval, the aventurine plaque inlaid with the Pantheon in Rome, width approximately 28mm