18k Gold Plated Emerald Green 1.8 Carat Cushion Cut Cubic Zirconia Engagement Ring Polished into a Lustrous Goldtone Finish. Feminine and elegant. Simple and sophisticated. Fashioned in luminous cubic zirconia this engagement ring is a lovely addition to any collection. 18k plated gold is achieved using an electroplating process that coats the item with heavy layers of 18k Yellow Gold and color-treated to display a perfect 14k Hamilton gold color.