Infused Stone is found throughout the world, it is an ore from Thaumcraft. There are 6 types of Infused Stone:
Fire, Water, Air, Earth, Vis, Dull.
The Infused Stones drop a few shards when mined.
Dull Infused Stone is created when the local Aura Node is running out of Vis, it then drains Vis out of the Infused Stone, keeping it balanced. When there is a lot of Vis in the Aura, regular stone can be converted into Infused Stone.