The largest D colour flawless diamond ever offered at auction will be sold through Christie's on May 15 in Geneva.

The rough diamond, weight 236 carats, was found at the Jwaneng mine in Botswana and took 21 months to polish

The spectacular pear-shaped diamond weighs in at 101.73 carats and is being offered for the very first time. One of the world's largest and most perfect diamonds, it is rated Type IIA Flawless.

An estimate has not yet been given for the gem, though it may well surpass the current record for a colourless diamond, which is held by the 76.02 carat Archduke Joseph diamond that sold for $21.5m at Christie's in November 2012.

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