Board Thread:Questions and Answers/@comment-78.89.230.66-20130121084635/@comment-5089372-20130121143841

Only way to get Diamond is by breeding dragons that collectively possess at least four distinct colors (Green, Red, Yellow, Blue, Purple or White). It's Ultra Rare so it takes lots of time and patience. Try the Diamond Dragon page for more info or the Breeding Calculator page and use the Breeding Possibilities section, it will show all possible combinations.

Also, things like level, rarity and name of the dragons used (and all the other things people say) do not matter. The only thing that matters is color pool. Good Luck To You!!