A single-row natural pearl necklace. Estimate £7,000 - 9,000 (€9,600 - 12,000). Photo: Bonhams.

The graduated row of 65 pearls, measuring from 3.0 to 8.7mm, with a natural pearl and brilliant-cut diamond cluster clasp, length 40.5cm

Accompanied by a report from GCS stating that all 65 pearls are natural, saltwater. Report number 5775-2109, dated 26 May 2015.

Accompanied by a report from SSEF stating that 55 pearls were tested and found to be natural, saltwater. Report number 77903, dated 19 December 2015.

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