Opal Jewelry: A Union of Beauty and Brilliance Opals are unique crystals that are formed through the interaction of silica and water, which results in the creation of tiny spheres that diffract light to display a myriad of colors. This play of color is what sets opals apart from other gemstones and makes them highly sought after for jewelry. Opal gemstone jewelry also has been connected with love, passion, and creativity throughout history. In some cultures, opals are believed to bring good luck and symbolize hope, purity and truth.