Gem Dragons

Vulnerability: fire

Claws and Bite +8 vs. AC (2 attacks) 10 damage

Natural 16+: The crystal dragon can make a crystalline breath attack as a free action.

[Special trigger] C: Crystalline breath +8 vs. PD (1d3 nearby enemies); 8 cold damage and the target is crystallized (stuck and unable to make attacks; normal save 11+ ends)

C: Shattering Scream: +8 vs. PD (1d3 nearby enemies); 6 thunder damage. If the target is crystallized, deal 2d6 extra damage and the encase effect ends.

Resist cold 16+: When a cold attack targets the crystal dragon, the attacker must roll a natural 16+ on the attack roll or it only deals half damage

Nastier specials:

Diamond claws: Humanoid targets are vulnerable to the crystal dragon's melee attacks.