A 118.28-carat white diamond broke a world record Monday when it fetched more than $30 million at a Hong Kong auction. The sparkling translucent stone was sold to a phone bidder at the Sotheby’s auction for HK$238.68 million ($30.6 million) following bidding that lasted for more than six minutes.

The egg-shaped stone has been described as the finest of its kind ever to appear at auction. Earlier estimates valued it at $28-$35 million.

The stone, dubbed the “Magnificent Oval Diamond”, was discovered in a deep mine in an undisclosed southern African country in 2011. As a rough stone before being cut, it weighed 299 carats.

The stone, described by Sotheby’s as “the largest D colour flawless diamond”, has been given the highest quality rating awarded by the Gemological Institute of America.