Crystalized Argentavis for the cave update

A bird who's made out of rocks and crystals. About the same height as a player. Can be found in large, open caves. Eats all kinds of crystals (amythests, diamonds, emeralds, etc.) The more crystals it eats, the more crystals will show on it's body. The more crystals on its body, the stronger and faster it is. The only way to tame it is to steal an egg from a nest underground, and incubate it with lots of light. Then feed it gems when it hatches so that it may trust you. When fully grown, you can ride it, however it requires a saddle.