[NEW YORK] An eye-popping, 100-carat diamond will be the highlight of a magnificent jewels sale in New York on Tuesday and could sell for up to US$25 million, Sotheby's auction house said.

The perfect classic emerald-cut D color diamond, which was mined by De Beers in southern Africa, is the largest to be offered at auction and one of only five of similar quality and size to ever to go under the hammer.

"The 100.20 carat diamond is the definition of perfection," said Gary Schuler, the head of Sotheby's jewelry department in New York.

"The color is whiter than white, it is free of any internal perfections, and so transparent that I can only compare it to a pool of water."

A flawless pink diamond, dubbed the "Pink Star," set a world record price for a gemstone at auction when it sold for US$83.02 million in Geneva in 2013. The highest price for a white diamond is US$30.6 million paid for a 118.28 carat stone in Hong Kong in 2013.

Mr Schuler said the distinguishing characteristic of the huge diamond being auctioned on Tuesday is its size and beautiful shape. Originally weighing over 200 carats, its owner spent more than a year perfecting its cut and polish.

Sotheby's said that from 1990 to 2013 the price per carat for a 100-carat perfect diamond had risen from US$125,000 to US$260,000. The US$19 million low end of the pre-sale estimate for the diamond being offered puts the per-carat price at US$190,000.

The diamond will lead the sale of more than 350 jewels that are expected to sell for a total of more than US$50 million.

Other highlights include a pear-shaped purplish pink diamond weighing 6.24 carats that has a pre-sale estimate of up to US$3.5 million as well as a blue diamond and colored diamond ring weighing 6.06 carats that could bring in as much as US$4.5 million.

Two Cartier Art Deco jewels, a rare platinum, emerald, sapphire, lapis lazuli and diamond pendant necklace as well as a ruby, emerald and diamond bracelet, will also be auctioned.

The Baron de Rothschild necklace is expected to sell for up to US$2.2 million and the bracelet has a pre-sale estimate of up to US$1.8 million.

Two Kashmir sapphire and diamond rings could each bring in US$1 million or more, according to Sotheby's.

REUTERS