Ross-Simons - 12.00ct Aquamarine Ring, Diamond Accents in 14kt Yellow Gold. Size 8. With an ethereal color and a touch of sparkle, this 12.00 carat oval milky aquamarine cabochon ring will take your ensemble to stylish new heights. Finely crafted in polished 14kt yellow gold with twinkling diamond accents flanking each side of the center gem. 1/2" wide. Aquamarine ring. Aquamarine birthstones are the perfect gift for March birthdays.