The Dresden Files: Portland
This crystal ball on a wooden base is rather opaque until activated with a True Name or drop of blood or some other symbolic link to a person or place. Then the cloudiness dissipates showing a scene.
Spell Provided: Essentially an extended divination spell of Complexity 6 for one scene, once per session (see page 297). A symbolic link to the target is required (blood, hair, True Name, etc.). The viewer may project a nearly-invisible spectral projection at the monitoring’s point of view—this could tip off an unaware but observant target. Uses 3 enchanted item slots. It can be used once per session.