In DragonVale for the Android and iOS systems (iPhone and iPad, etc.), the Diamond Dragon is the twelfth and final Gemstone Dragon to be introduced in the game, representing the month of April. Being a Gemstone dragon, it earns gems instead of gold and can not mate at all.
The Diamond Dragon has a base breeding time of 30 hours, sells for 1,750,000 gold, and earns 150,000 XP upon successful breeding at level 17.
To get a Diamond Dragon, breed an Ice Dragon with a Mine Dragon during the month of April. If you get an incubation time of 30 hours then you should be successful.
Check out my DragonVale Breeding Guide for more dragon breeding combinations, as well as the combinations you’ll need to make the necessary dragons for the Diamond Dragon, and other Gemstone Dragons.