The diamond—which is the size of a tennis ball—was unearthed in Botswana by the Lucara Diamond Corporation. Previous reports said it was expected to be worth a total of $70 million and net about $35 million for the company.

Large cut diamonds have fetched record prices. For example, an 813 carat diamond called “The Constellation” sold for $63.1 million back in May. It also set the record for being the world’s most expensive diamond. And another, a 14.6 carat diamond called the “Oppenheimer Blue,” sold for $57.6 million at an auction.

Normally large stones, like the ones listed previously, are offered to a handful of sophisticated dealers in the diamond industry. These dealers then study the diamond for weeks to determine how many cut stones the rough one will yield. Once they figure how much the stones will be worth, they submit a sealed bid to the mining company, according to the New York Times.

However, selling the Lesedi La Rona at a public auction breaks this tradition. In order to get the broadest exposure for Lucara’s record-setting find, the diamond corporation has been working with Sotheby’s and Julius Baer, a Swiss bank that has many wealthy private clients around the world, according to the Times.

Whoever buys the Lesedi La Rona, which means “our light” in Setswana, will pay Sotheby’s buyer’s premium, or a 12% fee, on the hammer price for anything over the first $3 million, and a higher percentage of the first $3 million. According to the Times, there is a reserve price below which Lucara would not sell, although that figure is not public.

Since the diamond could be cut to 400 carats, the hammer price does not include whatever the buyer would have to pay to have the stone cut, should he or she decide to do so.

“Nobody knows what a 400-carat diamond is worth,” said William Lamb, chief executive of the Lucara Diamond Corporation.