The Alchemist's Stone is a 300 skill recipe with a large amount of requirements that functions as a trinket that adds an increased effect to the health and mana potions you consume. It is also still listed as a requirement for making the Petrification Flask. Currently it is not confirmed whether or not the recipe for the Alchemist Stone is in the live game.

From Allakhazam:

Alchemists' Stone
Binds when picked up
Unique
Trinket Trade Goods
+8 Spirit
Requires Alchemy (300)
Passive: Increases the effects that healing and mana potions have on the wearer by 33%.

See also: http://wow.allakhazam.com/db/item.html?witem=13503

It seems this item still doesn't officially exist, though, so don't hold your breath.

Go to the main thottbott page and click on the word beta.  Go to professions and alchemy.  The trinket is pretty far down.

could u wear the same trinklet on both slots??
                >.<
would be the best thing for being an alchemist!!!

Says cost to make 107 gold but theoretically it costs nothing if you farm all the materials needed to make it.(I have already made the Skyfire & Earthstorm diamond)and am in process of collecting motes for the primal might right now, the most difficult bit is getting revered with the Shaa'tar but I am working on that. Even though I am a frost Mage and a number of the buffs would supposedly be of no use, I will be very happy to equip this trinket and can't wait to get it.