Cat’s-eye is a gem that produces a thin streak of white light across the top of the stone when the gem is cut a certain way. The streak resembles the pupil of a cat’s eye. The streak seems to change position as the stone is moved. This change is known as the chatoyant effect and is caused by light reflecting from tiny hollow channels within the stone. Cat’s-eyes display shades of yellow, green, red, and brown. They are used in jewelry and for other ornamental purposes. The term cat’s-eye used by itself describes only a semiprecious stone called chrysoberyl, also known as true cat’s-eye or precious cat’s-eye. Other types of cat’s-eyes have a specific gem name, such as tourmaline cat’s-eye. Most true cat’s-eyes are found in Sri Lanka.
