The 92-carat pendant suspended from a pearl sautoir is the showcase piece at Christie's spring sale, set for May 17 at the ultra-luxe Four Seasons des Bergues hotel on the shores of Lake Geneva.
Despite what Christie's calls the piece's "pure quality and magnitude", the necklace is unlikely to approach the jaw-dropping sums paid for smaller coloured diamonds in recent years.
In Hong Kong last month the 59.60-carat "Pink Star" fetched a record $71.2 million (65.1 million euros), a price that highlighted the galloping market for rare pink and blue diamonds.
Film buffs with a seat at the Christie's sale will also have the chance to bid on a set of ruby and diamond earrings and matching bracelet given to late Hollywood star Elizabeth Taylor in 1957 by her then husband, director and producer Mike Todd.
A total of 250 lots will be on offer at the auction, likely to be attended by high-end buyers from across the globe but especially Asia, a continent that has increasingly scooped up the world's most valuable stones.
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