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. In contrast, moonstone is identified by its captivating adularescence, a soft glow that appears to billow across the gem as it moves. This phenomenon results from light scattering caused by the inter growth of two different types of feldspar within the stone. Opal & Moonstones Comparison, both gemstones contain a unique optical effect that helps in determining the value of these crystals. The availability of play of color in opal is an important attribute that influenced its price as opals with vibrant and extensive play of color are highly cherished