The Earthy Gem is one of the eight Elemental Force Gems. Out of the four element gems, Earthy is the strongest and fediantly the most deadly. It's power's are many, and they include being able to create fissures, cause giant, jagged rocks tp shoot up from out of the ground, create walls of dirt, mud, or rocks, and finally shoot beams of earth elemental magic. It's form is a giant mantis with large claws. (think Snimon from Digimon)
Earthy appears in Episode 15 right in the middle of the gang's situation with Aquilia's depression spell. It emerges from the ground after opening numerous fissures, and causing many giant rocks to shoot out of them. Aquilia used her telekinesis to break the claws, while Sakura and Ceaira combine the powers of Water, Windy, and Firey to blast it before sealing it. When summoned, it's powers of earth can be harnessed. This is one of the five gems needed for Aquilia to return to her true form.