Moonstone

Moonstone is a variety of feldspar, typically composed of orthoclase and albite, with the approximate chemical formula (K,Na)AlSi₃O₈. It is characterized by its phenomenon of adularescence, a white, bluish, or silvery sheen that appears to float just beneath the surface of the stone when it is moved under light.

Its color ranges from white and colorless to gray, peach, yellow, or brown. It primarily forms in igneous rocks and often exhibits an internal structure of fine layers or exsolutions of feldspars responsible for its luminous effects.