Year: 2000 This is an authentic CARTIER 18K White Gold Moonstone Tank Ring 53 6.5. The ring is crafted of 18 karat white gold and features the iconic “Tank” band with a square moonstone cabochon in the center. This is a classic ring with the contemporary style of Cartier! Follow this item for alerts. Cartier is a registered trademark of Cartier. FASHIONPHILE is not affiliated with Cartier.