GIA Colored Stones Practice Test

The adularescence of the finest moonstone is characterized by a blue sheen, which is the most sought-after optical effect in this gemstone. Adularescence refers to the soft, billowy light that seems to float just below the surface of the stone, creating a glowing effect. In high-quality moonstone, this sheen typically appears as a distinct blue hue, resulting from the unique layering of feldspar minerals. These layers scatter light, and depending on the angle of the light and viewing position, the adularescence can appear quite strikingly. This blue sheen is a distinguishing feature that enhances the gem's appeal and is often used to evaluate its quality in the market. While other gemstone effects like color play or glows can be associated with different stones, the specific blue sheen is intrinsic to fine moonstone, making it a hallmark of its beauty.