3 Carat Cartier Diamond Ring in White Gold3 Carat Cartier Diamond Ring in White Gold. What a fabulous cocktail ring by Cartier featuring 3 carats of diamonds in a pave style finished in 18 karat white gold! The ring features a subtle off center curved design that adds an element of depth. One of the things that sets Cartier apart from many jewelers is their use of very white, very clear melee stones as they have with this cocktail ring. This ring is very striking yet still manages to be