GENEVA (AFP) - The largest flawless heart-shaped diamond has sold for US$14.99 million (S$20.9 million) in Geneva on Wednesday (May 17), breaking a world record in its category, auction house Christie's said.

The 92-carat diamond forms the centre-piece of a necklace of cultured pearls.

The sale price is a world record for heart-shaped diamonds, Christie's spokeswoman Alexandra Kindermann told AFP.

The piece was designed by Boehmer et Bassenge who have taken over the name of one of the greatest French jewellers of the 18th century.

It is now run by an Antwerp-based dimaond merchant.

The previous record for a heart-shaped diamond was set in 2011 when a 56.15-carat rock sold for US$10.9 million.