FABRICE COFFRINI/Getty Images
This 12.03-carat blue diamond fetched $48.4 million at auction on November 11, 2015, making it the world's most expensive diamond.
FABRICE COFFRINI/Getty Images
The fancy, vivid blue diamond was discovered in South Africa in January last year.
Christies
Just the day before, Lau purchased a 16.08-carat pink diamond from Christie's, dubbing it 'Sweet Josephine'. Set as a ring, it features a double row of pave-set white diamonds which surround the main stone.
Sothebys
Lau is known for his extravagant gifts and gestures. In 2009, he bought a 7.03-carat fancy vivid blue diamond for $9.48 million, which he named "Star of Josephine."
Sothebys
Lau has also purchased wildly expensive stones for his other daughter, 13-year-old Zoe. He bought this 9.75 carat diamond last year from the collection of the late Bunny Mellon for $32.6 million, the most for any blue diamond at the time, and named it 'The Zoe Diamond.'
Christies
He also bought for her 'The Zoe Red', a Burmese ruby and diamond brooch weighing 10.10 carats by Cartier for 8.43 million.
EMMANUEL DUNAND/AFP/Getty Images
In recent years, other high-value diamonds have hit the auction block. The 59.60-carat oval cut pink diamond known as "The Pink Star," went for $80 million at a 2013 Sotheby's auction. However, after the buyer defaulted on payment, it was returned to Sotheby's.
Peter Macdiarmid/Getty Images Europe/Getty Images
This 118.28 oval white diamond became the largest sold at auction when it went for $30.6 million at a Sotheby's auction in 2013.
Courtesy Sotheby's
In April, 100-carat, emerald cut, D color, internally flawless diamond -- the largest of its clarity and cut to ever be shown at auction -- sold for $22 million.
FABRICE COFFRINI/AFP/Getty Images
The 76.02-carat 400-year-old Archduke Joseph diamond set a new record for price per carat for a colorless diamond in 2012, when it sold for $21.5 million at a Christie's auction.
Courtesy Chow Tai Fook
In 2010, Hong Kong's largest jewelry retailer, Chow Tai Fook, bought one of the world's largest rough diamonds for $35.3 million.
Courtesy Chow Tai Fook
Jeweler Wallace Chan and a team of craftsman worked 47,000 hours to transform the stone it into this piece, which Chai Tai Fook estimates could be worth $200 million.

Story highlights

Billionaire buys two diamonds a day apart, and names both after 7-year-old daughter

The 'Blue Moon of Josephine' is the most expensive diamond in the world

CNN  — 

It weighs a hefty 12.03 carats. The color? An exceptionally fancy vivid blue. This month, the ‘Blue Moon’ diamond sold for a whopping $48.4 million, making it the world’s most expensive diamond.

Auctioneer David Bennett called it the “highest price per carat” ever obtained for any kind of stone. The record sale, which took place at a Sotheby’s auction in Geneva, was a headline in itself. But when the successful bidder renamed it, ‘Blue Moon of Josephine’, tongues were set wagging.

Just a day before, at a Christie’s auction, also in Geneva, an anonymous bidder purchased a 16.08-carat pink diamond, for $28.5 million. He dubbed it, ‘Sweet Josephine.’

01:07 - Source: CNN
World's most expensive diamond sold

Who is Josephine?

At first, the auction houses only disclosed that it had gone to a “Hong Kong buyer,” but the names of the diamonds provided clues to the purchaser’s true identity. CNN confirmed billionaire Joseph Lau, of property firm Chinese Estates Holdings, as the gem’s new owner.

“Yes, the diamonds were bought by Mr. Joseph Lau for his daughter,” his assistant told CNN over the phone.

Lau has a track record for naming gems after his daughters, 7-year-old Josephine and 13-year-old Zoe.

FABRICE COFFRINI/Getty Images
The diamond was estimated to sell for between 35 and 55 million dollars.

Back in 2009, Lau purchased a 7.03-carat blue diamond for $9.48 million. He named it, the ‘Star of Josephine.’

Sotheby's 'perfect' 100-carat diamond sells for $22 million

Last November, he purchased a 9.75-carat blue diamond for $32.6 million, calling it ‘The Zoe Diamond’ as well as a Burmese ruby and diamond brooch weighing 10.10 carats for $8.43 million, naming it ‘The Zoe Red.’

Lau is a prolific collector of art and wine, and has a penchant for extravagant gestures. He is the owner of a $17.4 million Andy Warhol portrait of Mao Zedong. He also built Hong Kong’s tallest retail complex and named it ‘The ONE’, reportedly after an ex-girlfriend.

According to Forbes, Lau is the 114th richest person in the world with an estimated net worth of $9.8 billion.

World records

The previous record holder for the most expensive diamond was the 24.78-carat Graff Pink, sold by Sotheby’s for $46.2 million in 2010.

In 2013, Sotheby’s auctioned a pink diamond called the ‘Pink Star’ for $83.2 million, but the buyer ultimately defaulted on the payment. The stone remains in the auction house’s inventory.

This week, an 1,111-carat diamond was discovered in Botswana by the Lucara Diamond firm. It’s currently the world’s second largest diamond of gem quality.