A Hong Kong tycoon has bought the 12.03-carat Blue Moon diamond auctioned at Sotheby’s in Geneva for a record $48.4 million.

Joseph Lau confirmed he bought the ring-mounted, cushion-shaped blue diamond for his 7-year-old daughter, renaming it “Blue Moon of Josephine” after her.

Sotheby’s said the sale had set “a new world auction record for any diamond of any color”.

It is not the first time Joseph Lau, a property billionaire, has bought precious stones for his daughter.

The businessman – who was convicted of bribery and money laundering in 2014 – is also confirmed as the buyer of a 16.08-carat pink diamond, which Christie’s sold for $28.5 million on November 10.

The pink diamond purchased earlier this week has been renamed “Sweet Josephine”, a spokeswoman for Joseph Lau said.

In 2009, Joseph Lau bought another blue diamond for his daughter – the 7.03-carat “Star of Josephine” – paying what was then a record $9.5 million.

The tycoon was sentenced to five years in jail after his corruption convictions in a Macau court, but has avoided prison by not visiting the territory. There is no extradition treaty between Macau and Hong Kong.

Sotheby’s spokesman David Bennett described Blue Moon diamond as “magical”.

“I’ve never seen a more beautiful stone,” he said.

“The shape, the color, the purity, it’s a magical stone and everybody, I think, who put it on their finger thought so.”

Two bidders were locked in a telephone bidding war for eight minutes before the hammer went down on November 11 sale, correspondents say, with the jewel not exceeding its pre-sale estimate of $35-$55 million.

The diamond was found in South Africa in January 2014 and its striking blue color is attributed to the presence of the element boron within its crystal structure.

It was named “Blue Moon” to reflect its rarity.

Experts say the market for colored diamonds has become increasingly strong in recent months, with both blue and pink diamonds attracting a lot of attention in jewel sales in Geneva.

Colored diamonds are among the rarest in the world, even ones that are not particularly vivid or clear.