A mid Victorian Holbeinesque enamel and gem-set gold pendant

A mid Victorian Holbeinesque enamel and gem-set gold pendant, centred with an oval-shaped aquamarine (possibly a replacement), within an openwork surround set with old circular-cut diamonds and rubies, the surround with polychrome enamel decoration and quartered with cushion-shaped chrysolites, suspending a further chrysolite drop, all set in gold with engraved decoration to the reverse, 7.5cm high