Ambient Dust

Miramai has Dust flowing in different densities across the planet. Dust Vessels are used to safely control the manipulation of Dust. However Ambient Dust is always near when a bit of extra power is needed. The Trinity of Magic placed physical limitations on the human body when manipulating Dust though. So while it is possible to draw power from the Dust that surrounds you, it will come with risk.
Just remember, it's one thing to borrow a small amount of power to move a little faster. It's entirely another to try and hold open a collapsing cave... The risk will often outweigh the reward.