What phenomenon causes the cloudy bluish white light observed in moonstone?

Adularescence is the phenomenon responsible for the cloudy bluish white light observed in moonstone. This optical effect occurs when light scatters between the thin layers of feldspar minerals within the stone. Specifically, moonstone is composed primarily of two types of feldspar that are layered together. When light enters the stone, it interacts with these layers, resulting in a soft, diffused glow that appears to float just below the surface, giving the stone its characteristic shimmering effect.

This unique dispersion of light not only adds to the aesthetic appeal of moonstone but also distinguishes it from other gemstones that might exhibit different types of optical effects. The other terms listed, such as luster and translucence, describe different attributes of gemstones but do not specifically relate to the shimmering characteristic of moonstone. Luster refers to the surface shine of a gem, while translucence describes the way light passes through a material. Iridescence refers to a play of colors that can change based on the viewing angle but does not encompass the soft blue glow typical of moonstone. Therefore, adularescence is the correct term for the phenomenon observed in moonstone.