The Crucible is a component of the Thaumatorium and a device used to conduct Alchemy. Both it and its more advanced counterpart, the Thaumatorium, require an active heat source, whether it be something as permanent as lava or a fire lit on netherrack, or a temporary flame generated by a burning log, for example. It must be filled with water as well, which must then be allowed to boil before Alchemy can be conducted using it. The Crucible can be filled manually, using buckets of water, or through mystical means, such as the Everfull Urn, which will keep the Crucible full indefinitely. Water does take time to boil, but this time can be decreased by attaching Arcane Bellows to the Crucible, but this is no longer necessary if one uses an Everfull Urn as the water added does not stop the current water from boiling. The water can be stood in, but will cause 1 point of damage per second if the water is boiling, and unlike previous versions will not add any aspects of Victus. The Crucible is created by using any Wand variant on a cauldron.
The main use of the Crucible, for any level of Thaumaturge, is to conduct Alchemy in. This is done by adding different items into the Crucible followed by a special item, a catalyst, to create a new item from said catalyst. Most all items are made up of aspects, as explained in the Aspects of Magic page. One of the ways of releasing these aspects is through boiling the items containing them in a Crucible to release them. By adding the catalyst in, the necessary aspects for the item being created, if present, are absorbed by the catalyst, taking on the qualities of the aspects it absorbed. However, as with near everything in the world of Thaumaturgy, nothing is without its risks, with Alchemy being no exception. Aspects that remain in a Crucible while water is present, as water is depleted as catalysts are added and items removed, it is possible for all the water in a Crucible to be depleted yet for aspects to remain, will slowly decay into Flux and enter into the Aura. This not only is a waste of the aspects, but also can lead to, over time, the dangerous buildup of Flux in the Aura, which can cause many a danger to any Thaumaturge. One must also take caution with Alchemy as, even if one does not intend to, they can easily add ingredients into the Crucible that fit recipes that have been researched. This will subtract aspects as usual, and can interfere with desired recipes, causing great waste. As so, it is advised to research the materials that one intends to use before attempting the recipe.