The guardians is the name given to a ter'angreal, or possibly set of ter'angreal in Far Madding that both prevent people from channeling around the city and detect channeling when it occurs, such as the use of a Well, or when a person Travels into the city (WH, Ch. 23, Ch. 24). In appearance, it is a disc a full span across that looks like clouded crystal, set into the floor and inlaid with a long thin wedge of clear crystal that point toward the chambers center. Metal collars surround the discs, marked off like a compass, but with ever smaller markings between the larger, which seem to be inscribed with numerals. When a man channels the clear wedges turn black and point to his location, for a woman they turn red (WH, Ch. 24).
The city posses a ter'angreal or perhaps it is three ter'angreal. No one knows. They – or it – cannot be studied any more than they can be removed removed”...“These ter'angreal duplicate a stedding. In the important ways at least, though I suppose an Ogier would not think so (Sarene, Winter's Heart, Chapter 23).