Rare fancy-colour diamonds, historic jewellery, and unique gemstones will appear at two Geneva auctions in November, headlined by an 8.63-carat pink diamond expected to fetch a hefty return. | Source: Sotheby's

Cartier bracelet set with a 197.80-carat Romanov Ceylon sapphire

Cartier necklace formerly owned by Mary Cavendish, Duchess of Devonshire

Sapphire and emerald toi et moi ring

Former royal demi-parure

1862 diamond tiara by Mellerio dits Meller