[Pocus]

no you need the master alchemist, to get 30 gp for each fire gem. Essentially, its a nature/fire/whatever please you rainbow mage. You have to find at least 3 nature gems a turn though, which is rather feasible by searching sites, or with diplomatical contacts. Once it is done, you income increase by 30 gp/turn. You can then stockpile for the Eternal Pyre (that you cast with your pretender) to get a nice +20 gems (600 gp). Thats basically that, an 'underground' gold strategy which cant be spotted and/or hampered by the others players.

An alternate path would be the blood stone one.