A crystal ball is a crystal or glass ball commonly used in fortune-telling. It is generally associated with the performance of clairvoyance and scrying in particular. Other names include crystal sphere, gazing ball, shew stone, and show stone. In neopaganism it is sometimes called an orbuculum.

Fortune telling is the unproven spiritual practice of predicting information about a person's life. The scope of fortune telling is in principle identical with the practice of divination. The difference is that divination is the term used for predictions considered part of a religious ritual, invoking deities or spirits, while the term fortune telling implies a less serious or formal setting, even one of popular culture, where belief in occult workings behind the prediction is less prominent than the concept of suggestion, spiritual or practical advisory or affirmation.