King Philip IV of Spain gave this blue diamond to his daughter in the 17th century.King Philip IV of Spain gave this blue diamond to his daughter in the 17th century. (Alastair Grant/Associated Press)

A grey-blue diamond sold for 16.3 million pounds ($30.3 million) at auction Wednesday in London, exceeding initial estimates significantly.

The 35.56-carat diamond, once owned by Spain's King Philip IV, had been expected to earn bids of up to nine million pounds ($16.7 million) at the Christie's auction.

The stone was purchased by Bond Street jeweller Laurence Graff.

The stone, known as the Wittelsbach diamond, is especially prized for its historic significance. Once passed down from King Philip IV to his daughter Infanta Margarita Teresa in the 17th century, it was later owned by the Wittelsbach family of Bavaria.

Christie's auctioned the diamond in 1931, and it re-emerged in the 1960s.

With files from the Associated Press