Can gold be transmuted in the Fullmetal Alchemist continuity? In the Fullmetal Alchemist manga/2009 anime, we learn that alchemists must obey three rules:


  Do not oppose the military
  
  Do the transmute gold
  
  Do not do human transmutation


Moreover, at one point in the early manga (probably chapter 3, according to Wikipedia), we see Ed transmute what appears to be gold from rocks, when he is duping Yoki into selling him rights to Youswell. (However, in the context of my question below, this might also be attributed to early-installment weirdness, since in the corresponding episode in the 2003 anime - episode 9 - I think we see Ed giving Yoki rocks that have been coated with gold from coins Ed got from Yoki.)

Both of the above seem to imply that transmuting gold is possible in the FMA universe, yet this seems to be contradictory given some other manga details. In the first chapter, we learn from Al that with alchemy, one can only transmute like from like. Being me, I read this to imply that the sort of conservation of mass alluded to when chemical equations are balanced generally applies in terms of what alchemy can do the FMA universe (at least in the more practical, mundane examples we see in the manga). (On a second read, I'm really not sure if that's a "correct" interpretation.)

Thus: is transmuting gold actually taken to be something possible in the FMA universe (or is it even possible to come to a conclusion about this)?
Yes, transmuting gold is possible (at least in the manga). The reason why it's forbidden is stated later in the series: It's forbidden so nobody can destroy the economy by making the gold worthless.

The mass is also conserved, I see no problem there. A ton of coal makes a ton of gold. Equal mass :).

Note: In the first adaption, Ed did not transmutate gold but instead coated the coal in gold. Either it's not possible in the 2003 anime or he didn't want to violate the law. (Thanks to キルア)