This is one of 4 Royal Gemstones. This is the Emerald dragon Phoebe, otherwise known at the "Nurturer" or the "Mother of the Crystal Dragons" in some folklore. She took care of the eggs when the other three died, she lived for a very long time before she died of old age.

Here she is~ on her tail there are very fine crystalline fibers that feel just like fur. Her tail is shorter so she could help out hatchings better and her scales blend in with nearby foliage and trees.

This is what he egg looked like.