An early 20th century natural pearl and diamond brooch, by Cartier. Photo Christie's Image Ltd 2012

Of star design, the bouton shaped natural pearl centre to a five ray surround, each pavé-set with old-cut diamonds with further pierced linear detailing, circa 1920, French marks for platinum, 6.6cm wide, original maker's case. Signed Cartier Paris Londres New York. Price Realized £58,850

Accompanied by report no.06548 dated 26 October 2012 from The Gem & Pearl Laborartory, London, stating the button-shaped pearl is natural, saltwater 

Christie's. Important Jewels. 12 December 2012. London, King Street