From Dragon Mania Legends (DML) Wiki
Stone Shield can be learned by all Dragons with the Earth Element. It is an active defensive skill that applies a positive status effect by absorbing incoming direct and/or indirect damage for two turns.
This skill is not stackable, therefore if two or more Dragons cast this same skill on a target, that target will have its defense raised to the strongest version.
This also applies to the Metal En Garde! defense skill.
Absorbs x incoming direct damage and y indirect damage for allied target, and z direct damage for other allies over 2 turns. Skill effectiveness is based on the caster's Dragon's Attack Strength (DAS).
Absorbs 120% DAS incoming direct damage for the allied target and 70% DAS incoming direct damage for others and the trained secondary effect occurs: