Cartier Ballon Bleu de Cartier 33mm 18-karat Gold and Stainless Steel Watch Cartier's unisex 'Ballon Bleu de Cartier' timepiece takes its name from the floating royal-blue cabochon that's nestled in the bezel. Its classic design forgoes flashy embellishments, instead opting for a sleek 18-karat gold and stainless steel bracelet - the links are curved to ensure it sits comfortably.