This is an authentic ROBERTO COIN 18K Rose Gold Diamond Black Onyx Amphibole Ring size 53 or 6.5. The ring is crafted of 18-karat rose gold, and features two offset squares of black onyx and diamonds weighing approximately .36 total carat weight. Follow this item for alerts. Roberto Coin is a registered trademark of Roberto Coin. FASHIONPHILE is not affiliated with Roberto Coin.