Which Is More Expensive: Opal or Moonstone? Opal is a mesmerizing gemstone known for its captivating play of color; it is an optical effect that has a wide range of colors. This phenomenon happens due to the diffraction of light as it passes through tiny silica spheres within the gemstone. Opals are found in Australia, which is a primary source of high-quality opals. Read More:https://shorturl.at/2p4uO #Opaljewelry #sagaciajewelry #gemstonejewelry #Moonstonejewelry