9ct Gold Synthetic Opal and Cubic Zirconia Cluster EarringsOpal and Zirconia Earrings These 9ct gold cluster earrings are designed around a central synthetic opal. This lab created stone displays a consistent, iridescent play of colour that shifts and flashes with movement. Encircling each opal is a halo of bright, white cubic zirconia stones which provides a sparkling contrast. The entire earring, including the setting and posts, is crafted from solid 9ct gold.