Transmutes in Cataclysm

Ever since epic gems became transmutable in Wrath, this has become the simplest and one of the most profitable specialties. It's still very profitable in Cataclysm. The easy money for any alchemist is the daily cooldown, shared by Truegold and Living Elements. Specializing in transmutation will mean you get 20% more Truegold over time, and it means a chance of getting an extra proc of random volatiles. The thing with the volatiles is that while you can force the primary result to be whatever is worth the most, you can't force the random transmutation proc.

The less automatic wow gold comes from transmuting gems. You can transmute rare gems from uncommon ones plus a couple of herbs. On any server where Elementium Ore is cheap, you can expect that the majority of rare gems will be available cheaper on the AH than their minimum price. They are prospected with the same frequency as all the other colors, but in addition, the uncommon red gems are used in manufacturing cheap enchanting mats. So if the price for Carnelians ever goes below about one-third of the price of a Greater Celestial, they get bought out by people who can craft and disenchant those weapons. The other gem you can transmute is the Shadowspirit Diamond. You get two of these for three of each uncommon gem. Interestingly, while flasks in Wrath also provided two flasks per craft, the transmutation procs for the meta gem does not yield 20% but awards the same number of bonus gems as if it was making them one at a time. Flasks used to proc four, six, eight, or 10, and these proc three, four, or five, seemingly much more rarely.