The world's largest commercially available diamond failed to sell under the auctioneer's hammer on Thursday.
Experts at Sotheby's in Geneva had predicted the as-yet unnamed diamond could be the most expensive stone ever to be sold.
But the 103-carat diamond failed to reach its minimum asking price of $8.5 million by just under $1 million.
The 1995 auction of a slightly smaller diamond - the Star of the Season - fetched more than $16.5 million.
It took diamond cutters in South Africa and the US 18 months to perfect the gem that went up for auction in Switzerland on Thursday evening.
Large crowds flocked to Sotheby's to view the gem.
"Only three diamonds over 100 carats have ever been sold at auction and one of them, according to rumour, is being worn as a
ring," the BBC's Imogen Foulkes in Geneva says.
She added that the owner of the diamond would also win the right to give it a name.
But the diamond will now remain nameless, at least for the time being.
Guy Jennings, president of Sotheby's Switzerland, declared the lot not sold.
The diamond took centre stage at the auction in Geneva, Europe's capital for gemstone sales.
On Wednesday the auction house's rival, Christie's of Geneva, sold the largest sapphire ever to go under auction in a set of sales that generated more than $25 million.
Sapphires are among the most durable gemstones
The overall figure is the auction house's best result in 10 years and was $7-to-10 million more than it expected to raise.
Sotheby's Mr Jennings had expressed optimism prior to the auction of its unnamed diamond, saying the world's wealthiest bidders appeared to have been unaffected by the economic downturn.