A type of fortunetelling called "scrying" involves gazing into a reflective surface as an aid to clairvoyance. Meaning "clear seeing," clairvoyance is the alleged ability to see beyond the normal sensory range. It is therefore a form of supposed extrasensory perception (ESP). Polished metal or stones have been used. The reputed seer Nostradamus (Michel de Notredame, 1503-1566) employed water in a brass bowl upon a tripod when he practiced scrying. Today the most common device is a crystal ball— either a polished quartz crystal or a glass sphere (as shown here).
Scrying involves the would-be visionary relaxing and emptying his mind, while staring at the reflective surface. In time it may become cloudy, then black, following which images may appear. These may be symbolic forms that need interpreting, or they may be pictorials— like snapshots or even moving film. It is said that only about one person in twenty is able to "see" anything by scrying.
Believers attribute the "gift" to natural psychic power, which is said to manifest itself in childhood. Rosemary Ellen Guiley (Harper's Encyclopedia of Mystical and Paranormal Experience, 1991) observes that scryers in Arab countries are children under the age of about eleven whose "natural gifts" subsequently diminish.
Skeptics suspect that those who are able to scry successfully are merely highly imaginative individuals with a strong capacity to fantasize and visualize. They point out that there is no scientific proof that anyone is actually clairvoyant.