This article is more than 4 years old

This article is more than 4 years old

A Hong Kong billionaire spent a record $48.4m buying an 12.03-carat diamond dubbed “Blue Moon” for his seven-year-old daughter in an auction in Geneva.

Property tycoon Joseph Lau bought the rock at a Sotheby’s auction on Wednesday and immediately renamed it “Blue Moon of Josephine” after his daughter.

The sale comes the day after he spent $28.5m buying a rare 16.08-carat pink diamond – the largest of its kind to ever go under the hammer – from rival auction house Christie’s, which he rebaptised “Sweet Josephine”.

A Hong Kong-based spokeswoman for Lau confirmed the two purchases. “The first was the pink one, ‘Sweet Josephine’, and the second one was the ‘Blue Moon of Josephine’,” she said.

David Bennett, the head of Sotheby’s international jewellery division, said the “Blue Moon” sale broke several records and made the gemstone the most expensive diamond, regardless of colour, and the most expensive jewel ever sold at auction. It also fetched the highest-ever price per carat, he said.

The previous world record for a jewel sold at auction was held by the 24.78-carat “Graff Pink” diamond, which was sold by Sotheby’s for $46.2m in November 2010.

This is not the first time Lau has bought rare jewels for his daughter. In 2009, he reportedly spent $9.5m on another blue diamond, which he renamed the “Star of Josephine”.

Josephine is his daughter with girlfriend and former aid Chan Hoi-wan, according to local media. The 64-year-old also has two children with long-time partner Yvonne Lui.

In March 2014, Lau was found guilty of bribing a former minister in the gambling enclave of Macau in an attempt to purchase a prime development site. Lau, who was not in Macau for the sentencing, is unlikely serve time because the two semi-autonomous Chinese cities do not have an extradition agreement.

He was locked in a telephone bidding war for eight minutes for “Blue Moon” before the hammer went down, with the precious jewel staying within its pre-sale estimate of $35m-$55m.

The diamond was discovered in South Africa in January 2014 and was the largest cushion-shaped blue stone in the fancy vivid category to ever appear at auction.

Experts say the market for coloured diamonds has grown increasingly robust and both the blue and pink diamonds garnered a lot of attention in the run-up to this week’s jewel sales in Geneva.