Gems are items that give your monsters stat bonuses (HP, Attack, Magic, Speed, Defense, or Resist). They can be equipped in the Hero menu that can be accessed in any town. In order to equip gems, you will need a particular breeding license. 

There are four types of gems: Oval, Square, Tear, and Star.

Gems can also come in the "embued" flavor, which allows them to give two different stat bonuses. 

Color Ranking

1 Topaz (Gold)

2 Ruby (Red)

3 Emerald (Green)

4 Amethyst (Purple)

5 Sapphire (Blue)

6 Aquamarine (Light Blue)

Licenses Required

Apprentice License: Oval Gem

Veteran License: Square Gem

Elite License: Tear Gem

Master License: Star Gem