Quicksilver is a common crafting reagent used in early-middle game.
Crafting[]
Quicksilver has many ways to be created. Crafting together 9 Quicksilver Drops, 1 Shimmerleaf, or smelting a Cinnabar Ore gives 1 Quicksilver, while smelting a Native Cinnabar Cluster gives 2.
Use[]
The only use for Quicksilver in vanilla crafting is to make 9 Quicksilver Drops, but it can be used to make items such as Wand Focus: Equal Trade in Thaumcraft crafting, as well as being usable in Infusion.