The Oppenheimer Blue

The Oppenheimer Blue is known as the second on the list of most expensive gemstones and the largest diamond of its kind ever sold at auction. In 2016, a final bid of $58 million was placed on the magnificent 14.62-carat diamond.

Surprisingly, the bidding for this rock took more than 20 minutes. "It felt that for those 20 minutes the diamond belonged to everyone as they celebrated each bid the stone received," someone in the room remarked during the auction.

The Oppenheimer Blue was named after Sir Philip Oppenheimer, one of the company's previous owners. Sir Philip was a member of the De Beers Mining Company family, which also controlled the Millenium series.

Price: $58 million

Year Sold: 2016

Number of Carats: 14.62

Interesting Fact: This was the largest diamond of its kind to appear at auction