Once per hour, a Chosen of Mystra can unleash from within his or her body a beam of magical whitish flame known as silver fire (which is also used as a general name for the overall power invested in each of her Chosen by the goddess). This beam is 5 feet wide and can be made to extend as far as 70 feet if desired. No magical or physical barrier has been discovered that can stand up against it, and the beam inflicts tremendous damage on all beings struck by it. Any nonliving object touched by the beam is utterly destroyed. An individual also can choose to expel the silver fire in the shape of a cloud that fills a cone-shaped area 5 feet in diameter at its base, up to 70 feet long, and up to 70 feet across at its widest. This silver cloud causes no damage, but banishes dead magic areas forever, instantly restoring such an area's connection with the Goddess of All Magic. This use of the silver fire is extremely rare, since Mystra considers it an emergency action only.
The silver fire also can be activated within the body of a Chosen to purge all external magical and psionic compulsions from that person. And, once per day, an individual can teleport without error to the last location where he or she used the silver fire in any of its forms.
It should also be noted that silver fire is composed of pure Weave magic energy, thus the clashing of silver fire with pure Shadow Magic will cause the multiverse to unravel itself, tearing the fabric of the world, causing huge dimensional rifts between the planes. As has happened in Shadowdale in the Year of Wild Magic (1372 DR), when Elminster was fending off several invading Shadow Princes, who were actually shadow-mattered creatures. His silver fire did vaporize one of them, but also created a rift between Toril and the Nine Hells.  Elminster jumped into the Nine Hells and sealed the rift from there, but such an act also burned all his magical energies and left him entirely helpless in the Hells. Only with the help of the Simbul did the archmage finally escape.
A portion of a Chosen's silver fire can be used to hold the knowledge of how to cast a particular spell within a Chosen's mind. While held in this way, these spells can be cast by silent force of will alone, without the need for verbal, somatic, or material components.