November 13, 2015 | Jewelry
The Blue Moon: a stunning 12.03 carat fancy vivid blue internally flawless diamond | Photo: Sotheby's

Hong Kong investor Joseph Lau bought two rare diamonds for $77 million at back-to-back auctions held in Geneva, Switzerland.

In the first auction held at Christie's, Lau paid $28.5 million to buy "The Pink," a 16.08 carat cushion-shaped fancy pink diamond. The new owner renamed it "Sweet Josephine," in honour of one of his daughters.

"As large and rare coloured diamonds of this calibre become increasingly hard to locate, this diamond comes to market at a time when great gems are mirroring prices achieved for masterpieces in the world of fine art," underlined Rahul Kadakia, Head of Jewelry at Christie's International.

Twenty-four hours later, Joseph Lau paid $48.5 million at Sotheby's to obtain "The Blue Moon," a stunning 12.03 carat fancy vivid blue internally flawless diamond. The stone displays the highest possible color grading for blue diamonds, and was renamed "The Blue Moon of Josephine."

The Pink: a 16.08 carat cushion-shaped fancy pink diamond | Photo: Christie's

The rare blue diamond set a new record of more than $4 million per carat. It was cut from a The 29.62-carat rough blue diamond discovered in the famous Cullinan Mine, in South Africa.

Strong saturated colored diamonds are rare; blue diamonds are even rarer. "The Blue Moon" was studied by scientists from the Smithsonian Institution and the National Gem and Mineral Collection because of its unusual red phosphorescence, which can be observed when the stone is exposed to ultraviolet light.

Joseph Lau owns 61 percent of Chinese Estates Holdings. Forbes estimates that the Hong Kong billionaire's fortune is of $11.5 billion.