A 12.03-carat blue diamond has been auctioned at Sotheby's in Geneva for $48.4m (£31.7m) to a Hong Kong tycoon.
Joseph Lau confirmed he bought the ring-mounted, cushion-shaped stone for his daughter, renaming it "Blue Moon of Josephine" after her.
He is also confirmed as the buyer of a 16.08-carat pink diamond, which Christie's sold for $28.5m on Tuesday.
Lau, a convicted property billionaire, has a history of buying precious stones for his daughter.
In 2009, he bought another blue diamond for her - the 7.03-carat "Star of Josephine" - paying what was then a record $9.5m.
The pink diamond purchased earlier this week has been renamed "Sweet Josephine", a spokeswoman for Mr Lau told BBC News.
Last year he was sentenced to five years in jail in Macau for corruption, but has avoided prison by not visiting the territory. There is no extradition treaty between Macau and Hong Kong