SRD:Light

This spell causes an object to glow like a torch, shedding bright light in a 20-foot radius (and dim light for an additional 20 feet) from the point you touch. The effect is immobile, but it can be cast on a movable object. Light taken into an area of magical darkness does not function.

A light spell (one with the light descriptor) counters and dispels a darkness spell (one with the darkness descriptor) of an equal or lower level.

Arcane Material Component: A firefly or a piece of phosphorescent moss.