Potions

There are nine basic potions:

Inversion
This potion, when thrown, drunk, or mixed, inverts its target. Mixing with a ruby makes a sapphire, mixing with a topaz makes an emerald, and the reverse.

Change
This potion, when thrown or drunk, randomly polymorphs its target. Some monsters may resist.
 * Mixing with any potion besides Inversion or Permanence results in a random potion selected from the remaining 7 basics.
 * Mixing with any gem makes a random gem of a different color.
 * Potions of Transformation into a specific monster can be created by mixing the remains of that monster into a Potion of Change.

Duplication
Drinking this potion has no effect.
 * Mixed with any potion besides Inversion, or Dissolution results in a duplicate, and the original is not lost.
 * Thrown, it duplicates a hit monster. (do domesticated/peaceful dupes have a chance of being hostile?)
 * version 1.2 mixing with an amulet causes a crash, but gives you the chance to save. restoring is fine, and you lose the potion, but not the amulet.

Energy
Drinking or throwing causes the target to have full MP.
 * Mixing with remains charges like dipping in a fountain of energy; failure does not waste potion.
 * Mixing with your mage staff acts like charging once. A Serious waste of a potential life saver.
 * Mixing with any gem charges it. This is important because you can't even charge topaz in a fountain of energy.
 * Charged remains or gems can be attached to the staff.

Life and Death
The potions of life and death are quite similar, with undead targets having exact opposite effects, simply switch the two for dealing with undead.
 * Drinking a potion of life heals completely, and drinking a potion of death kills instantly.
 * Throwing a potion of life causes a living target to have full HP. undead targets are hurt.
 * Mixing with remains revives the monster (as an undead if potion of death is used), and will probably become an ally, there is a chance of it being peaceful or hostile, depending on the monster's IQ.

Absorption

 * Drinking in its pure form removes all MP.

Dissolution
When used or thrown, a Potion of Dissolution will remove added special effects (like Polymorph or Haste) from the target, similar to a Cloud of Primal Order. Note that this will not remove effects natural to the monster (Fire Resist for a Red Dragon, for instance).

It can also be Mixed with another object to separate it into two components. e.g.
 * Amulet of Reversal + Pot. of Dissolution = Amulet + Pot. of Inversion
 * Pot. of Energy + Pot. of Dissolution = Pot. of Absorption + Pot. of Inversion
 * Mage Staff w/ Item attached + Pot. of Dissolution = Staff and item seperated

Permanence
Drinking this potion lengthens the duration of effects on the target.
 * Mixing with a worn item will add 500 turns to its duration.
 * Mixing with a potion-infused Crystal Ball or charged remains/gem will add ~3-8 charges. (can't be mixed while on staff)

There doesn't seem to be any cap on the number of turns/charges.

Advanced Potions
There are potions which can only be created through mixing, and cannot be found in the dungeon.
 * A potion of Change mixed with remains creates potion of Monster Transformation.
 * A potion of Absorption can be mixed with many remains creates a Potion of Absorbed Effect.
 * A potion of Absorption can also be mixed with a gem to produce a potion to temporarily resist fire, cold, poison, or lightning, depending on the gem used.
 * A potion of Permanence can make potions of Gain Energy, Gain Life, and Final Death by mixing with the respective basic potion.

Basic Potion Mix Table
*Gain Energy, Gain Life, and Final Death are advanced potions but react identical to their base potions in this mix chart. They are still properly duplicated, however.