A Catalyst is an object that can be embedded into a Mana Weapon to amplify a specific element or combination of elements.
A Catalyst can be either natural or man made. It is usually a shard of crystal that when Mana Energy is pumped though it, one or more elements get amplified.
Catalysts can be used for more than just Mana Weapons, they can be used to amplify Mana in many devices. Even primitive peoples could use a Catalyst to boost the potency of a spell without any technology.
Some cultures regard Catalysts as religious artifacts with godlike powers.