Crystals are minerals containing magical properties. These artifacts are used by witches and other magical beings in spells and rituals. Different types of crystals are used in different manners and may have various functions.
Crystals may be used to create a defensive barrier or as a detection system for evil beings. By spreading crystals around a house, one can create a "magical alarm system" to detect the presence of evil. Users may also take a crystal elsewhere to alert them if a location has been breached. These crystals may also be charged with magical energy to prevent beings from entering the protected location.
Scrying is one of the basic powers possessed by witches. It is the ability to locate lost objects or beings by using a scrying crystal. Scrying is used by holding a crystal over a map. Once an object or being is located, the crystal will begin swinging, which will increase the closer it gets to the target. When the location is clear, the crystal will pinpoint it on the map.
Another function is the creation of a crystal cage. When a witch charges five crystals and places them in a pentagram, the crystals will connected through beams of energy or electricity and create a barrier to trap those inside. Beings inside are unable to leave physically or through teleportation. When they try to escape, they may be electrocuted.
Over the years, the Charmed Ones have used crystal cages to trap evil beings, for instance to interrogate them. By using a sixth crystal, they could electrocute those inside and torture them for information. Crystal cages have the limitation that beings can be freed by outside forces, by moving the crystals or by breaking through with pure force.