Joseph Lau was the top bidder for the 12.03-carat Blue Moon diamond that sold on Wednesday night for a record-setting 48.6 million Swiss francs (£31.8 million), a spokeswoman for Mr Lau said.
He was also the buyer of a 16.08-carat vivid pink diamond that sold for 28.7 million Swiss francs (£18.8 million) auctioned by Christie's the night before, she added.
Mr Lau renamed the pricier gem The Blue Moon Of Josephine and the pink diamond Sweet Josephine.
The blue diamond, set in a ring, was said to be among the largest known fancy vivid blue diamonds and was the showpiece gem at the Sotheby's jewelry auction.
The Blue Moon - named in reference to its rarity, playing off the expression "once in a blue moon" - topped the previous record of 46.2 million dollars (£30.4 million) set five years ago by the Graff Pink, Sotheby's said.
The diamond also set a new record of more than four million dollars (£2.6 million) per carat, capping the high-end jewellery sale that reaped roughly 140 million dollars (£92 million).
Mr Lau, a property developer with a fortune estimated by Forbes at 9.9 billion dollars (£6.5 billion), has a habit of snapping up expensive gems for his children.
At a Sotheby's auction in Geneva in 2009, he bought another blue diamond, paying a then-record 9.5 million dollars (£6.3 million) for the 7.03-carat Star Of Josephine.
Last November, he also bought two gems for another daughter, 13-year-old Zoe, his spokeswoman said.
One was a 9.75-carat blue diamond that he named Zoe Diamond after buying it for about 33 million dollars (£21.7 million) at a Sotheby's auction in New York.
He also spent 65 million Hong Kong dollars (£5.5 million) on a 10.1-carat ruby and diamond brooch at a Christie's auction. He named that one Zoe Red.
Mr Lau was sentenced to more than five years in prison last year by a Macau court after he was found guilty of bribery and money laundering.
But Mr Lau, who did not attend the trial, has remained free by avoiding travel to the former Portuguese colony, which does not have an extradition treaty with nearby Hong Kong.
Both cities are specially administered Chinese regions.
Auctioneer David Bennett said in Geneva on Wednesday: "Tonight we set a new world record, a new auction record for any diamond, any jewel, any gemstone, with the sale of the Blue Moon diamond."
He specified the price as 48,468,158 dollars (£31,879,736), adding: "I have never seen a more beautiful stone. The shape, the colour, the purity - it's a magical stone."
The polished blue gem was cut from a 29.6-carat diamond discovered last year in South Africa's Cullinan mine, which also yielded the 530-carat Star Of Africa blue diamond that is part of the British crown jewels, and the Smithsonian Institution's Blue Heart discovered in 1908.
Sotheby's says experts took five months for an "intense study" of the original Blue Moon diamond, and a master cutter took another three months to craft, cut and polish the stone.
The auction house said the Cullinan mine was the "only reliable source in the world for blue diamonds", and only a tiny percentage of those found in it contain even a trace of blue.