Priyantha Gems

Cat’s-eye effect, or chatoyancy, is a very special optical phenomenon. It refers to the effect that shows a bright band of light on a gemstone’s surface, which resembles the eye of a cat. This effect comes from a gemstone’s abundant needle-like inclusions, rutile crystals or hollow tubes, which scatter the light. This effect is best displayed when the gemstone is fashioned into a cabochon.
In general, only the chrysoberyl with cat's-eye effect can be directly called cat's-eye. Its body colour ranges from yellow, yellowish-green, to green.
Another rare type of cat’s eye gemstone is cat’s-eye alexandrite, which on top of its colour-changing effect, displays a cat’s-eye effect. It is one of the most sought-after gems for collectors.
The cat’s-eye effect is not limited to a single type of gemstone; on rare occasions, emerald, tourmaline, quartz, spinel, etc. can also display this phenomenon.