Reflex saves for magical beasts are good. Reflex should be +12.
Given that these creatures appear to be quadrupedal, reach should be 5 feet, not 10 feet.
What's the Rend damage?
Special qualities say half damage from fire/ice (which should be cold, not ice, presumably), but Crystalline Body says half damage from fire and acid.
Why do these earth-based creatures have a swim speed, especially such high speed compared to land speed?
Refraction: Store how? Refract how? How many targets? Range of what? How does the storing and releasing work?
Shard Spray: Damage seems low for the level, and compared to just attacking (a single claw attack deals more damage).