Sotheby's has described the 75 carat diamond it is to offer on April 17 as "the most valuable white diamond ever to appear at a New York auction".

Although the 75 carat diamond may exceed the current $21.5m world record price for a colourless diamond at auction, Christie's is offering a 101.7 carat example in May, which appears a stronger contender

Valued at $9m-12m, the stone is one of only a handful of pear shaped, D-colour diamonds in excess of 50 carats to be brought to auction in recent decades. Remarkably, a second D-colour pear shaped diamond, weighing in at a slightly more impressive 101.7 carats, is to auction at Christie's Geneva on May 15.

Let the battle of the diamonds commence…

Although an estimate for Christie's gem is yet to be published, it may well surpass the current record for a colourless diamond sold at auction, which is held by the 76 carat Archduke Joseph Diamond that sold for $21.5m at Christie's in November 2012.

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