A natural pearl and diamond brooch-pendant. Estimate £10,000 - 12,000 (€14,000 - 16,000). Photo: Bonhams.

The openwork quatrefoil plaque with a central natural pearl of grey tint, within a scrolling surround decorated with smaller grey natural pearls and rose-cut diamonds, suspending a drop-shaped natural pearl of grey tint, measuring 14.2mm, brooch length 5.5cm, fitted case 

Accompanied by a report from The Gem & Pearl Laboratory stating that the pearls are natural, saltwater. Report number 08764, dated 22 October 2013.

 Bonhams. FINE JEWELLERY, 24 Sep 2015 12:00 BST - LONDON, NEW BOND STREET