Alchemy

A technically abundant but fiendishly difficult form of magic. Allows users, “alchemists,” to “transform” one thing into another. Remote, but some seem to be born with a “gift” for it.

Effect

The inner workings of alchemy are unknown, but it is said that alchemy trades an object's rejected material with the adopted material of something else in the universe that is more valuable in this situation---while the rejected material is of equal or greater value in the situation the adopted material is leaving.
When the trade is of equal value, it can be undone. Say one turns lead to gold---perhaps the Remaining World lead is replaced by gold from a moon. Neither lead nor gold has any use to anyone on the moon, so the gold can be transformed back into lead (the lead is "recovered"). When the trade is of unequal value and both parties happen to gain, it cannot be undone. Perhaps the gold, instead of coming from the moon, came from a person who has too much gold but not enough lead. Now they suddenly have lead, which is more valuable than the gold was. By nature, alchemy increases the value of a material, so the reversal cannot be made.
(Note: this is a misunderstanding. Recoveries cannot be made if the rejected material has been altered in the foreign environment---for example, if the lead on the moon was struck by an asteroid and damaged or the person who magically received it melted it. Skilled alchemists can recover slightly altered materials, but since it's altered, that's generally not desirable.)

Side/Secondary Effects

Since alchemy is completely remote, there's no inherent cost to the alchemist, not even over repeated uses. However, alchemy also hints at darker, unknown magic, as getting it wrong results in confusing and often violent accidents: mutation, instantaneous combustion, change of state of matter, or fracturing of the object may result in harm to the alchemist.
Attempting alchemy on living organisms tends to lead to painful, grotesque disasters, though it is rumored that highly skilled alchemists can replace their dying flesh with healthy flesh. This ability is considered by some to be a sign of divine favor, while most consider it a horrific taboo (where does the flesh come from?).

Manifestation

Successful alchemy is rumored to smell like smoke.

Source

Disputed

Material Components

In order to perform alchemy on an object, it needs to be worked by a tool. Generally, the more appropriate the tool is to the object, the more successful the alchemy is. For example, using a spinning wheel to work straw to turn it to gold is more appropriate than hitting straw with a spoon; however, a pitchfork would work better. The most skilled an alchemist is, the more leeway they have with this.
Some amount of the target adopted material is also needed to be touching the rejected material. There is a certain ratio that must be met for the alchemy to work; this is the trickiest part of alchemy, as it can only be done by guesswork and trial-and-error. Alchemists rarely survive enough tests to get themselves a feel for this ratio, but some are born with this feeling and tend to have successful guesses.

Gestures & Ritual

The rejected material is worked together with the proper amount target adopted material using an appropriate enchanted tool.

Effect Duration

The transformation is permanent unless recovered or transformed into something else.

Effect Casting Time

Larger or more complicated materials need to be worked for longer amounts of time, but even this is generally brief.

Range

Only the object being transformed is affected.

Applied Restriction

There are laws against certain kinds of alchemy in some areas due to the potential dangers of error and the taboo of living transformations.