The cat's eye gemstone is actually a chrysoberyl. The word chrysoberyl is derived from the Greek words for golden and green beryl, but chrysoberyl and beryl are not the same stone at all. The term cat's eye is derived from the phenomena displayed by this stone known as chatoyancy, which in French means "cat's eye." This is the changeable luster the stone exhibits when a light shines into the cabochon-cut gem.
Cat's Eye has been treasured for many centuries, and is believed to be a powerful protective stone, particularly against evil spirits. Chrysoberyl has long been considered a good luck charm in numerous cultures. Cat's eye's color ranges from a golden honey to grey to mint green. Cat's Eye is not the same mineral as Tiger's Eye, which is a quartz.
Cat's eye is rated at 8 to 8.5 on the Mohs scale of hardness, making it a tough, durable gemstone suitable for all jewelry purposes.