Counterspell

Counterspell was an abjuration spell that attempted to stop another spell from being cast.

Effect
If a creature within 60 feet (18.3 meters) of the caster attempted to cast a spell, then the caster could make a instant reaction to attempt to counter it. If the spell was of the same spell level as counterspell, then it would end but if it was more powerful it had a chance of failing. If the caster wanted to interrupt a spell of higher level she could cast counterspell as a higher level spell, if the targeted spell had the same level or lower then it would be stopped.

Components
Only a somatic component was needed.