A remarkable 17.97 ct. Burmese ruby is expected to achieve between $4.8 million and $5.5 million in Phillips’ highly anticipated Geneva Jewels auction on Nov. 11.

Rubies above 10 carats are considered true anomalies in nature, so one nearing 20 is exceedingly rare. This particular ruby, set in a ring with diamonds (pictured at top), also boasts impressive clarity, vibrant unheated color, and deep saturation.

Another prized lot in the sale is an internally flawless, type IIb 3.24 ct. fancy vivid blue diamond ring, estimated to sell for $4.8 million to $6 million.

“On the heels of Phillips’ successful Jewels sale in Hong Kong, which achieved an outstanding 89% year-on-year increase, we are excited to unveil the highlights of the Geneva Jewels Auction: Three,” said Benoît Repellin, Phillips’ worldwide head of jewelry, in a statement.

“This sale presents an extraordinary collection of treasures, featuring a stunning Burmese ruby, a rare fancy vivid blue diamond, and distinguished pieces with historical significance, alongside classic jewels from prestigious houses. The sale includes captivating unheated natural sapphires and rubies, as well as emeralds with no clarity enhancements.”

Phillips is showcasing sale highlights on a global tour, visiting London, Paris, Singapore, and New York this month. The online catalog goes live on Oct. 21, with a preview beginning on Nov. 6 at Geneva’s Hotel President, where the auction will be held.