(IDEX Online) - A 24.45-carat heart-shaped diamond fetched just over $2m in an online auction by Christie's.The Type IIa stone was graded by GIA as D color, internally flawless, excellent polish and symmetry.It was set in a platinum pendant necklace with a 1.37-carat, D-color, internally flawless pear-shaped stone.The piece, headlining the Summer Sparkle sale, sold for $2.01m. Its pre-sale estimate was $1.55m to $2.55m. A total of 51 lots sold for $5.1m. The second highest-grossing piece was a 9.83-carat VS1-clarity fancy vivid orange-yellow round-cornered rectangular modified brilliant-cut diamond ring. It sold for $810,000, slightly above its $600,000 to $800,00 estimate.Pic courtesy Christie's