Crystal Dragon

Breeding
The can be bred by selecting a Lightning Dragon or lightning hybrid dragon to mate with an Earth Dragon or earth hybrid dragon at the Breeding Cave/Epic Breeding Island.

Breeding a Lightning Dragon with an Earth Dragon can also result in a Quake Dragon.

Earning Rate
Coin per minute: Level 1: 8 / Level 10: 48

Dragon Earning Rates without boosts.

Boost Calculation Guide to use with the page linked above.