The Cat's Eye gemstone, also known as Chrysoberyl, is a unique and captivating stone that exhibits a striking optical phenomenon called chatoyancy. This effect creates a narrow band of light that resembles a cat's eye, which moves across the surface of the stone when it is rotated. The gemstone is typically yellowish-green but can also be found in shades of brown, gray, and even blue. Cat's Eye is valued not only for its beauty but also for its durability, ranking 8.5 on the Mohs scale of mineral hardness. It is often used in jewelry, particularly in rings and pendants, and is believed by some to bring good luck and protection to its wearer.