Silver fire

In-Game Statistics
Excerpt from Forgotten Realms Campaign Setting, p. 56

This powerful supernatural ability is unique to the Chosen of Mystra. Manifesting as a beautiful silver-white flame that surrounds the wielder and fills the area into which it is projected, silver fire can be used for different effects. It can act as a ring of warmth or a ring of mind shielding, allow the user to breathe water, or banish all external magical compulsions upon the user as if a greater dispelling spell were cast upon her. Only one of the above effects may be used at any time. The user can call upon silver fire to revitalize her, allowing her to function without food or drink for up to seven days. (This funciton can only be used once a tenday.) Once every 70 minutes she may unleash silver fire as a blast of flame. This blast may be in an area 5 feet wide and up to 70 feet long, breaking through barriers as a lightening bolt would and overcoming magical barriers and spell resistance automatically. This blast deals 4d12 points of fire damage (Reflex half DC 23). Alternately, the silver fire can be unleashed in a 70 foot cone, dealing no damage but permanently restoring dead magic zones within the cone to normal and dispelling (as a greater dispelling spell) any antimagic field effects that contact the cone. This cone effect is draining on the Weave, and Mystra discourages its use except for emergencies. All effects function as if cast by a 20th-level sorcerer.