A 6.03-carat blue-diamond ring is likely to fetch as much as CHF 9.5 million ($12.2 million) at an upcoming Sotheby’s sale in Geneva.

The ring centers a cushion-shaped, fancy-vivid-blue, internally flawless, type IIb stone. It will be among the top pieces at the May 12 High Jewelry auction, according to the auction house’s website.

Sotheby’s will showcase lots from famous designers, including Van Cleef & Arpels, Bucherer and Cartier, as well as pieces featuring colored diamonds and gemstones.

Here are more of the top lots:

A pair of unmounted brilliant-cut, 18.38-carat, D-flawless diamonds, both classified as type IIa at Sotheby's imageA pair of unmounted brilliant-cut, 18.38-carat, D-flawless diamonds, both classified as type IIa at Sotheby's imagePresale estimate: CHF 2.2 million to CHF 2.8 million ($2.8 million to $3.6 million)
A pair of unmounted brilliant-cut, 18.38-carat, D-flawless diamonds, both classified as type IIa.

A necklace featuring a graduated fringe of 13 drop-shaped Colombian emeralds weighing between 11.38  and 57.52 carats and centering an 11.56-carat cabochon emerald in a frame of baguette, old mine-, old European- and single-cut diamonds at Sotheby's imageA necklace featuring a graduated fringe of 13 drop-shaped Colombian emeralds weighing between 11.38  and 57.52 carats and centering an 11.56-carat cabochon emerald in a frame of baguette, old mine-, old European- and single-cut diamonds at Sotheby's imagePresale estimate: CHF 800,000 to CHF 1.6 million ($1 million to $2 million)
A necklace featuring a graduated fringe of 13 drop-shaped Colombian emeralds weighing between 11.38  and 57.52 carats and centering an 11.56-carat cabochon emerald in a frame of baguette, old mine-, old European- and single-cut diamonds.

An unmounted pear modified brilliant-cut, 4.12-carat, fancy-pink, internally flawless, type IIa diamond at Sotheby's imageAn unmounted pear modified brilliant-cut, 4.12-carat, fancy-pink, internally flawless, type IIa diamond at Sotheby's imagePresale estimate: CHF 800,000 to CHF 1.6 million ($1 million to $2 million)
An unmounted pear modified brilliant-cut, 4.12-carat, fancy-pink, internally flawless, type IIa diamond.

The Peacock of Ceylon is an unmounted cushion-shaped, 102.40-carat Ceylon sapphire at Sotheby's imageThe Peacock of Ceylon is an unmounted cushion-shaped, 102.40-carat Ceylon sapphire at Sotheby's imagePresale estimate: CHF 1 million to CHF 1.5 million ($1.3 million to $1.9 million)
The Peacock of Ceylon is an unmounted cushion-shaped, 102.40-carat Ceylon sapphire.

A ring centering a pear-shaped, 14.60-carat, fancy-brownish-orangey-pink, VS1-clarity diamond, with its gallery including brilliant-cut diamond accents at Sotheby's imageA ring centering a pear-shaped, 14.60-carat, fancy-brownish-orangey-pink, VS1-clarity diamond, with its gallery including brilliant-cut diamond accents at Sotheby's imagePresale estimate: CHF 650,000 to CHF 950,000 ($828,977 to $1.2 million)
A ring centering a pear-shaped, 14.60-carat, fancy-brownish-orangey-pink, VS1-clarity diamond, with its gallery including brilliant-cut diamond accents.

A ring with two marquise-shaped, D-color, internally flawless diamonds of 6.68 and 7.20 carats at Sotheby's imageA ring with two marquise-shaped, D-color, internally flawless diamonds of 6.68 and 7.20 carats at Sotheby's imagePresale estimate: CHF 560,000 to CHF 800,000 ($714,190 to $1 million)
A ring with two marquise-shaped, D-color, internally flawless diamonds of 6.68 and 7.20 carats.

A Bucherer necklace featuring five step-cut Colombian emeralds weighing between 3.08 and 13.24 carats, pavé-set throughout with brilliant-cut diamonds at Sotheby's imageA Bucherer necklace featuring five step-cut Colombian emeralds weighing between 3.08 and 13.24 carats, pavé-set throughout with brilliant-cut diamonds at Sotheby's imagePresale estimate: CHF 480,000 to CHF 800,000 ($612,104 to $1 million)
A Bucherer necklace featuring five step-cut Colombian emeralds weighing between 3.08 and 13.24 carats, pavé-set throughout with brilliant-cut diamonds.

A Cartier bracelet from around 1950 stars an oval, 7.04-carat Kashmir sapphire bordered by brilliant-cut diamonds, within an openwork geometric baguette and brilliant-cut diamond design at Sotheby's imageA Cartier bracelet from around 1950 stars an oval, 7.04-carat Kashmir sapphire bordered by brilliant-cut diamonds, within an openwork geometric baguette and brilliant-cut diamond design at Sotheby's imagePresale estimate: CHF 400,000 to CHF 630,000 ($510,087 to $803,377)
A Cartier bracelet from around 1950 stars an oval, 7.04-carat Kashmir sapphire bordered by brilliant-cut diamonds, within an openwork geometric baguette and brilliant-cut diamond design.

A Van Cleef & Arpels necklace sporting a detachable pendant that can be worn as a brooch, designed as a cluster of pear- and marquise-shaped and brilliant-cut diamonds hanging from a subtly graduated necklace composed of alternating clusters of brilliant-cut and pear-shaped diamonds at Sotheby's imageA Van Cleef & Arpels necklace sporting a detachable pendant that can be worn as a brooch, designed as a cluster of pear- and marquise-shaped and brilliant-cut diamonds hanging from a subtly graduated necklace composed of alternating clusters of brilliant-cut and pear-shaped diamonds at Sotheby's imagePresale estimate: CHF 425,000 to CHF 625,000 ($541,961 to $797,013)
A Van Cleef & Arpels necklace sporting a detachable pendant that can be worn as a brooch, designed as a cluster of pear- and marquise-shaped and brilliant-cut diamonds hanging from a subtly graduated necklace composed of alternating clusters of brilliant-cut and pear-shaped diamonds.

Main image: The 6.03-carat blue-diamond ring. (Sotheby’s)