Opals are linked to light and magic, possibly because of their lively appearance. As a result, some people believed that opals had therapeutic qualities, particularly for the eyes. Some people thought that wearing opals could even make one invisible. Some people wear opals for good luck, while others hold onto unfavorable superstitions about them. As the stone is rotated, some opals can exhibit a phenomena called play-of-color, which is characterized by brilliant bursts of color.