In general, the term is used to mean staring into something—often a shiny surface, but not always—for the purpose of divination. Visions that are seen are often interpreted intuitively by the person who is scrying. It’s a popular method of divination and can be done in several different ways. Scrying is a form of divination that involves staring into a reflect surface. Practitioners look at a mirror, fire, or water in hopes of seeing images and visions. The visions that are seen during a scrying session often provide hints of things to come in the future.
We’ve all seen images of the old fortune teller woman peering into a crystal ball, hissing, “Cross my palms with silver!” but the reality of it is that people have used crystals and glass for scrying for thousands of years. By focusing on the ball, which is usually made of a clouded glass, a medium may be able to see visions that foretell not only the future but unknown aspects of the present and past.
Alexandra Chauran, over at Llewellyn, says, "The crystal ball exercises the part of you that sees your intuition expressed in a visual form, while keeping a safe boundary between your psychic practice and your everyday life... As you practice, you may find that the actual tiny flecks that inspire you to see shapes in the crystal ball allow you to see other fleeting visions within the crystal ball itself that are more akin to real visions right before your eyes."
Most practitioners believe that seeing things while scrying is possible for anyone, because everyone has some latent degree of psychic ability. Once you learn basic techniques of scrying, and what to look for, it becomes second nature. Continue reading from Learn Religions
Scrying with a Mirror & More (WikiHow)
Scrying: How To Develop This Ancient Divination Skill (The Traveling Witch)
Divination by Scrying: A Second Sight (Llewellyn)
Mirror, Mirror on the Wall: A Guide to Scrying (The College of Psychic Studies UK)
Through the Obsidian Mirror (Getty Research Institute)
Early 20th Century Crystal Ball (Rosenberg Library Museum)
Scrying Mirror: How to Make and Use One (Learn Religions)
Scrying: Its History, Traditional Tools, and How to Do It (Exemplore)
Crystal Balls: The Ultimate Guide To Its Origins And How To Use (Tiny Rituals)