[Source: Reuters]

The largest internally flawless fancy vivid blue diamond ever put up for auction could sell for up to $50 million at a Christie’s sale of rare jewels in Geneva on Nov. 7, the auctioneer said.

Known as “Bleu Royal,” this vivid blue diamond – which is set in a ring – is among the rarest ever to be unearthed.

“What makes Bleu Royal so rare and special is its size. At 17.6 carats, it’s the largest of its kind,” said Rahul Kadakia, Christie’s international head of jewellery.

“The colour is very rich naturally, and it is internally flawless as best as can be.”

In 2016, Christie’s sold a rare, 14.6-carat blue diamond known as the “Oppenheimer Blue” for more than $57 million.

“We hope it will beat the Oppenheimer,” Kadakia said of “Bleu Royal.”

“We have toured it all around the world, to Asia, to the U.S. and Europe, and we’ve had good interest from collectors worldwide.”

In a separate online auction running Nov. 3-16, Christie’s will be offering a pearl necklace worn by film and fashion icon Audrey Hepburn in the final scene of the movie “Roman Holiday” from 1953.

“We priced it at $20,000 to $30,000, so it’s quite reasonable,” Kadakia said. “Everybody can be Audrey Hepburn.”

The auctioneer will also be presenting a Rolex wristwatch worn by Marlon Brando in the 1979 movie “Apocalypse Now,” on the back of which the actor engraved his signature to avoid having it swapped accidentally during shooting.

“What makes it truly unique is that it is really one of the most recognizable memorabilia Rolex that has ever surfaced at auction,” said Remi Guillemin, head of watches in Europe at Christie’s.

Two years ago the watch, now valued at between 1 million and 2 million Swiss francs, sold at auction for $2 million Swiss francs ($2.2 million).

“It is indeed highly exceptional to have both pieces from incredible actors – a Rolex from Marlon Brando and a necklace from Audrey Hepburn,” Guillemin said.