Alchemy specialization works quite differently from all the other profession specializations in the game. Instead of gaining access to new recipes, you get a chance to create an extra item whenever you make potions, elixirs, or transmutes, depending on what you're specialized in. I've chosen Elixir Specialization (I don't make a lot of pure potions and too many people doing transmute spec will ruin the economy), and I haven't gotten any procs yet. A guildmate of mine did Transmutation Specialization and got two Primal Mights out of one, the lucky so-and-so.
Minkyminky of Feathermoon brings up an excellent question on the forums when she asks "If you're paying someone to make potions, elixirs or transmutes with your mats, who gets any extras -- you or the alchemist?" My first inclination is that the alchemist should keep the extras. After all, I did the elixir specialization quest and had to collect all the materials to do it. You paid me for five Onslaught Elixirs, and five Onslaught Elixirs is what you're gonna get -- any extras are a result of my time and my work into the specialization. This is a bigger question with transmutation, since transmutes are on a cooldown and produce much more expensive results. Who wouldn't want an extra primal might? Plus, the customer is the one seeking out the alchemist. If a person goes into the deal saying "If your transmute spec procs, I want the extra," they're probably not going to get that transmute done.
Beltira of Aegwynn is a transmute specialist who's come up with an ingenious system. She advertises, "375 Alch Transmute Specialist available: 10g for xmute - I keep proc, 50g for xmute - you keep proc." If the customer pays 10g and the specialization happens to proc, it's too late, they can't change their mind. Basically, the customer is paying extra for a chance at more loot -- kind of like a lottery. Some other people add that they plan to keep an "extra primal might" in their backpack and trade it at the time of the transmute. Then later on, they'll do the transmute with the mats they got and keep whatever comes out, thus avoiding the whole problem.
I still think any extra potions, elixirs or transmutes should be the property of the alchemist, but I understand the other view. What do you think?