The Ponahalo Diamonds, the two rectangular stones cut from a 316.15-carat piece of rough mined in South Africa, sold for more than $6 million at a Christie’s auction held on Wednesday in New York City.

The buyer, Amer Radwan of Radwan Diamond and Jewelry Trading in Dubai, United Arab Emirates, paid $4.11 million for the 102.11-carat Ponahalo diamond, while the smaller stone, weighing in at 70.87 carats, sold for $2.15 million.

The Ponahalo diamonds are the world’s largest Forevermark stones. Forevermark is the diamond brand recently launched by De Beers.

The stones were the highlight of Christie’s “Jewels: The New York Sale” and “Superb 20th Century Jewels from an American Collection” sales, held on Wednesday in New York City. The sales totaled $29.4 million.