Deco Emerald Cut Aquamarine Diamond Ring in Platinum.  This dazzling cocktail ring features a beautiful light blue 3.50 carat aquamarine with .12 carats of accent diamonds on the shoulders and is set in platinum. The prong set aquamarine is just an excellent size for a cocktail ring, being large enough to make an impression but not too large to turn it into a hand workout. This stunning ring will be a cherished piece in your collection.