In 2014, a 29.6-carat blue diamond was discovered in the Cullinan mine in South Africa—the same place the Smithsonian Institution’s famous “Blue Heart” was dug up in 1908. The stone was whittled down into a flawless, 12.03-carat gem and dubbed the “Blue Moon” diamond. It’s since been exhibited at the Natural History Museum of Los Angeles County (NHM), and studied by the Smithsonian. It’s also been described as one of the rarest gems in the world. Now, it belongs to a 7-year-old girl in Asia.

According to The New York Times, the Blue Moon diamond was purchased yesterday at Sotheby’s Magnificent Jewels and Noble Jewels sale in Geneva by a Hong Kong billionaire named Joseph Lau. Lau—who’s been convicted of corruption and is valued at $9.9 billion—paid a record-breaking $48.5 million for the unusual mineral, and re-named it “The Blue Moon of Josephine” after his daughter. It reportedly sold for more than $4 million per carat, topping the previously historic sale of the “Graff Pink,” a 23.88-carat pink diamond that was acquired for $46.2 million five years ago.

What makes blue diamonds like the Blue Moon so valuable? According to the NHM, diamonds gain their hues from color centers, which the museum defines as “single or multiple non-carbon atoms that replace carbon in the structure of the diamond, causing a disturbance in the structure and sometimes giving rise to the color.” Blue Moon gets its vivid blue hue from trace amounts of boron in its crystal structure—a rare chemical impurity that makes the diamonds much more scarce than their clear counterparts.

The stone will join other elaborate gifts in Josephine’s jewelry box, including a 16.08-carat vivid pink diamond that Lau also purchased yesterday from Christie’s (he calls it “Sweet Josephine”) and the 7.03-carat blue “Star of Josephine” diamond, which Lau snapped up via Sotheby’s in 2009. It kind of makes you wonder—if these are the types of gifts Josephine’s getting now, what will be left to give her for her 16th birthday?

[h/t New York Times]

All images courtesy of YouTube.