© Licensed to London News Pictures. 06/04/2018. LONDON, UK. A model presents a 50.39-carat oval diamond (top) and a 51.71-carat round brilliant-cut diamond (bottom) at a photocall at Sotheby's, New Bond Street. They are two of the largest, purest white diamonds ever to come to auction, have a combined estimate in excess of US$15m and will be sold at auction in Geneva on 15 May.  Photo credit: Stephen Chung/LNP
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