I can't seem to find out how to breed a diamond dragon in Dragonvale. I've tried quite a few combos in the Epic Breeding Island, but none work for me. Anyone know a confirmed combo? I've heard it's Mine and Ice, but it doesn't work. Do they need to be a certain level? I really need a gemstone dragon.
I can confirm that the combo you're looking for is: Ice + Mine. Since this is a Gemstone dragon, it is not obvious that this is the pair you need. Another consequence of it being a Gemstone is that this is the only possible pairing, and you can not breed more by having two. Your dragons don't need to be any special level, but if they are over 15 you have a better chance. Also, the EBI will give you slightly better chances than the breeding cave, so if you are spending gems to speed up breeding, I recommend prioritizing the EBI.
Personally, I've found this one quite hard, perhaps the hardest of the Gemstones (diamond pun for you :) ). With the long fail times of Quicksilver, Steel, Silver, and Platinum, you end up waiting a long time with each failed attempt. The month is still early, so keep calm and breed on.