Transmute: Primal Water to Shadow
From WoWWiki
Transmute: Primal Water to Shadow allows an alchemist to change a [Primal Water] into [Primal Shadow]. This requires a [Philosopher's Stone] and triggers a 20-hour transmute cooldown.
Source
This is a rare transmute that does not have a recipe. The only way to learn it is to "discover" it.
Alchemy Discovery:
You have a small chance to discover a recipe from a specific list of discoverable recipes every time that you perform a transmutation or that you make a potion, elixir, or flask that was introduced in the Burning Crusade. The discovered recipe is learned automatically. Non-factors include physical location, level, and skill level.
Notes
[Mote of Shadow] was made very rare after 2.1, and more patterns have been added that require [Primal Shadow]. [Primal Shadow] now auctions for the same as or more than [Primal Water]. As a consequence, this transmute has become much more attractive than it originally was.

