A Christie's employee displays "Bleu Royal," a rare 17.61-carat internally flawless fancy vivid blue pear-shaped diamond, during a preview at the Christie's, in Geneva, Switzerland, Nov 2, 2023. (PHOTO / KEYSTONE VIA AP)

GENEVA - The largest internally flawless fancy vivid blue diamond ever put up for auction sold for a staggering $43.8 million at a Christie's sale of rare jewels in Geneva on Tuesday, the auctioneer said.

The vivid blue diamond, known as "Bleu Royal" and set in a ring, is among the rarest ever to be unearthed. At 17.6 carats, the diamond had an estimated value of up to $50 million prior to the sale.

"The stone made almost $44 million," said Rahul Kadakia, Christie's international head of jewelry.

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"It's a huge amount of money given what's going on in the world today."

In a separate sale on Monday, Christie's sold a Rolex wristwatch worn by Marlon Brando in the 1979 movie "Apocalypse Now" for more than 4.5 million Swiss francs ($4.99 million)

Max Fawcett, head of Christie's jewelry department in Geneva, said the diamond was unique because of its deep rich blue color and its unmodified pear brilliant shape.

"It really ticked all the boxes, which is why we managed to excite collectors all around the world, all the way from the Far East, also to America," he said. "We're extremely delighted with the result."

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At its auction on Tuesday, Christie's sold dozens of rare jewelry pieces worth a combined total of more than $77 million.

"It's clear that the market is still very strong in certain areas," Fawcett said.

A Christie's employee displays "Bleu Royal," a rare 17.61-carat internally flawless fancy vivid blue pear-shaped diamond, during a preview at the Christie's, in Geneva, Switzerland, Nov 2, 2023. (PHOTO / KEYSTONE VIA AP)

"Coloured stones performed extremely well, as did signed jewelry... There's a great market out there for rare things, and there are still collectors looking for the very best."

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In a separate sale on Monday, Christie's sold a Rolex wristwatch worn by Marlon Brando in the 1979 movie Apocalypse Now for more than 4.5 million Swiss francs ($4.99 million).

The actor had engraved his signature on the back to avoid having it swapped accidentally during shooting.

Two years ago, that same watch sold at auction for 2 million Swiss francs.