A large oval-shaped diamond known as the "Pink Promise" was sold to an anonymous buyer for $32 million in Hong Kong on Tuesday, just short of shattering a world auction record.

The 14.93-carat vivid pink diamond went for a final price of HK$249,850,000, which comes to $2.14 million per carat, to an international private collector at Christie's autumn sale.

The price fell short of breaking the previous world auction record for the most expensive pink diamond per carat, which was set in 2009 when a cushion-shaped fancy vivid pink diamond went under the hammer for $2.155 million per carat.

"The colour of the stone was at the very top end of the pink diamonds, for pink. The size was very important, almost 15 carat, so you have an important size, a top colour, absolutely clean stone and beautifully cut. So all of those elements together factored into the perfect masterpiece helped us achieve this price," said Rahul Kadakia, Christie's International Head of Jewelry.

The world record price paid per carat is $4.03 million for the Blue Moon of Josephine, a 12.03-carat, cushion-shaped fancy vivid blue diamond that Hong Kong tycoon Joseph Lau bought in a 2015 Sotheby's auction, according to the Guinness World Records. Lau named the $48.5 million diamond after his daughter.