A Seer is someone who can use the gift in such a way so that they can "see" the way events play out in visions and possibly predict the future, but cannot use the gift as wizards and sorceresses do. The visions of a seer are often metaphoric, and they also have the ability to see the aura of a person.
Seer's Magic Edit
A seer's gift allowed them various 'sight' related abilities. When a seer saw a person they were able to naturally view a person's 'aura'. The aura of a person was described as being the 'physical form of that person's emotions and beliefs. A seer was able to discern what a person was experiencing emotionally from reading their aura, as well as what was causing those emotions and how strong they were. There is also indication that auras reveal a person's intentions. For example, when Jebra Bevinvier first met Richard Rahl, she was able to see the violence in his past, and that he wanted to start a fight.
The main aspect of a seer's magic was their visions. The visions were a form of vague prophecy that seers were able to experience. However, seers were not able to control these visions. They were triggered by the seer reading someone's aura. A seer did not always see a vision when they read an aura, but when they did the vision almost indefinitely involved the person who triggered it.
Seer's visions came in two forms, metaphorical and literal. Literal visions were basically viewing an event that has yet to happen. These visions always came true and, even though the vision showed them a future event, did not always happen they way the seer expected. In this way seer differentiated themselves most from prophets but were compared to witch women.
The second form, metaphorical, were much akin to the visions of prophets. In these visions the seer would be shown scenes of various signs, symbols and events that had meaning different from the literal sense. Literal visions were much more uncommon then metaphorical, probably because metaphorical visions were usually concerned with events not as important as prophecy.
The strain of the emotions and pain could often overwhelma seer, causing her to collapse or experience fits of pain, quite possibly both. The Seer's Stone most seers wore helped focus their power, as to relieve the trauma of the visions. Despite that it was still very hard for a seer to use their power, causing most to wish for death.