Feed The Beast Wiki
This page is about the Thaumcraft 4 Crucible. For other uses, see Crucible.

ModThaumcraft 4
TypeSolid block

The Crucible is a block added by Thaumcraft 4, used to create various items.

TC4 Crucible.png


The Crucible is created by right-clicking a Cauldron with a Wand (no Vis is used).


The Crucible is filled by right-clicking it with a Water Bucket, or using a form of pipes.

The Crucible must be "powered" with a heat source directly underneath the block; either Fire, Lava or Nitor will work.

When the Crucible is filled, after a couple seconds, it will begin to boil- small bubble particles will appear from the surface of the water (those particles may be different colors if Essentia is in the Crucible). If the Crucible is not boiling, it cannot be used to create anything.

Two things are needed in order to create anything: Essentia and a Catalyst.

Essentia is collected by throwing items into the Crucible, after which they are broken down into their Essentia components (for example, a Torch would give 1x Lux).

Once the Crucible is filled with the Essentia a recipe requires, a Catalyst is used to complete the recipe by throwing it into the Crucible. Doing so will use up the Essentia needed for the respective recipe and the completed item will be able to be picked up as a result. Any remaining Essentia is left in the Crucible.

Essentia in the crucible is constantly degrading; Compound Essentia will deform into its component aspects and Primal Aspects evaporate over time. This can cause adverse effects.

Similarly, the Crucible can be emptied with a right-click of the wand. All the Essentia will be dumped into the atmosphere which cases such adverse effects such as Flux Goo spillage, Flux Gas and Tainted Slime spawning. Effects vary based on the amount of Essentia wasted.

While wearing the Goggles of Revealing or similar, player can view the exact contents of a Crucible by looking at it.

Example recipe




Thaumonomicon entry

To craft the Crucible, you must simply use your wand on a cauldron placed in the world.
The crucible is an important tool for any thaumaturge. It allows him to render physical objects into their component Essentia and recombine it again as he wishes.
The crucible needs to be placed over a source of constant heat and filled with water. Once the water starts boiling you simply throw any items you wish into the crucible and they will be broken down into their component Essentia.
If you know the proper formula and the mix of essentia within the crucible is correct, you can then drop a special item into the crucible known as a Catalyst. The catalyst draws the essentia into itself and transforms into a whole new item that the crucible then ejects.
Any leftover Essentia remains within the crucible for further use, but it is not a good idea to leave essentia within a crucible for too long.
Crafting also uses some of the water within the crucible and you will eventually need to refill it.
Essentia within the crucible is constantly degrading. Compound essentia degrades into one of its component aspects, and Primal essentia simply evaporates.
Beyond the waste of resources, evaporating and degrading essentia can cause many strange side-effects.
You can empty a crucible by shift right-clicking on it with a wand. All the essentia is dumped into the atmosphere... not something you would want to do too often.