A natural pearl, ruby and diamond brooch, third quarter of the 19th century. Photo: Bonhams.

The openwork cartouche set with a central natural pearl, old brilliant and rose-cut diamonds and cushion-shaped rubies, within a scalloped frame of black enamel and engraved decoration, suspending a swag of similarly cut rubies and diamonds, terminating in a graduating fringe of drop-shaped natural pearls, mounted in yellow gold, diamonds approximately 1.40 carats total, length 6.5cm. Estimate £12,000 - 15,000 (€15,000 - 18,000)

Accompanied by a report from Laboratoire Française de Gemmologie stating that the six pearls are natural. Report number 196437, dated 30 November 2011.

Bonhams. FINE JEWELLERY. London, New Bond Street, 30 Apr 2014 - www.bonhams.com