Cat’s eye refers to all gems that exhibit a cat’s eye effect. This effect is calledchatoyancy, which means that the gemstone tends to show light in a narrow band of gemstone width, perpendicular to the inclusions in the gemstone. This effect is most obvious inchrysoberyl.
Chrysoberyl is present in three types of beryllium aluminate. chrysoberyl is yellow-green and transparent. Cymophane or cat’s eye is another variant of chrysoberyl. It is lime to yellow in color, translucent, and can be used as a gemstone. The third type is called alexandrite, which is a gemstone that presents three colors when viewed from three different directions, namely red, emerald green, and orange/yellow.