On November 13th, 2012 Christie’s Geneva auctioned one of the world’s most important diamonds, the Archduke Joseph, for $21.5 million. The 76.02 ct, D-color Internally Flawless cushion cut went for more than $280,000 per carat, a new record for colorless diamond.

The stone is from the ancient Golconda mines of India, which were the world’s only diamond source until the early 18th century. Some of the most spectacular diamonds have emerged from the Golconda region, including the Koh-i-Noor and the Hope.

Archduke Joseph diamond courtesy Robert Kane/Fine Gems International, Photo ©Tino Hammid.

The diamond is named for one of its illustrious owners, Archduke Joseph August (1872–1962), a Hungarian prince of the Habsburg dynasty. When it last went on the auction block, at Christie’s Geneva in 1993, the diamond sold for only $6.5 million. It was subsequently recut to improve its clarity and brilliance.

Photo Courtesy Robert Kane/Fine Gems International, Photo ©Tino Hammid.