Green moonstone is a common name for garnierite, a nickel-magnesium silicate ore. It has similar properties to moonstone, which is a feldspar mineral that can appear in a variety of colors, including green. Moonstone's shimmering glow, also known as adularescence, is caused by light scattering between thin layers of feldspar crystals. The layers separate as the mineral cools, and when light passes through them, it scatters in many directions, creating a soft, glowing effect that seems to move across the stone's surface.
Moonstone is often found in igneous rocks, so it's best to look for it in areas that were once active magmatically, rather than dry sedimentary rocks. Some popular places to hunt for moonstone in the U.S.
