In DragonVale for the Android & iOS systems (iPhone and iPad,e tc.), the Gold Dragon is a Treasure Dragon similar to the Silver Dragon, Platinum Dragon, and Bronze Dragon.
The Gold Dragon has a base breeding time of 48 hours, sells for 5,000,000 coins, and earns 600,000 XP for successful breeding once you reach level 17.
To get a Gold Dragon, you need to breed a fire type dragon with a metal type dragon. Popular combinations are plain Fire +Metal or Fire + Steel since these have low chances of breeding other types of dragons. If you get a 48 hour incubation time then you’ve probably got it.
Check out my DragonVale Breeding Guide for more dragon breeding combinations.