Paris Hilton's engagement ring from Carter Reum features an emerald cut diamond ranging from 10 to 15 carats and could retail for anywhere between $1 to $2.5 million (between about £700,000 to £1.7 million). Hilton revealed that the emerald-cut diamond was designed by Atelier of Jean Dousset, and the brand even ended up naming it "Paris" after her.