A sapphire and diamond necklace, by Kern. Photo Christie's Image Ltd 2014

The rectangular cut-cornered sapphire weighing approximately 16.22 carats, to a marquise-cut diamond three stone surmount, suspended from an articulated box-link necklace, channel-set to the front with baguette-cut diamonds, with polished backchain and concealed clasp, 43.7cm long. Estimate £16,000 - £18,000 ($26,784 - $30,132). Price Realized £140,500 ($234,776)

Accompanied by report no.09866 dated 9 May 2014 from The Gem & Pearl Laboratory, London, stating the 16.23 carat sapphire is natural with no evidence of heat treatment observed

Christie's. IMPORTANT JEWELS,4 June 2014,London, King Street -http://www.christies.com/