A conch pearl and diamond pendant. Photo Christie's Image Ltd 2013

The pear-shaped openwork old brilliant-cut diamond pendant suspending a diamond capped conch pearl swing centre, to a diamond and conch pearl drop and surmount, suspended from a trace-link chain, pendant 5.7cm long. Estimate £1,600 – £2,000

Accompanied by report no. 05172 from The Gem & Pearl Laboratory, dated 31st January 2012, stating that the conch pearls were found to be natural. 

Christie's. JEWELLERY.4 September 2013. London, South Kensington