Gems are a core customization system in Children of Mana, allowing you to enhance your character's abilities, weapons, and even recovery items. You equip gems into your Gem Frame, which can be expanded three times throughout the game (details in the [GEMS] section of the FAQ). Gems come in various colors, each generally associated with different types of effects:

- Red Gems: Often boost physical attack or weapon-specific abilities.
- Blue Gems: Typically enhance magic power, MP, or spell effects.
- Yellow Gems: Provide utility, such as movement speed, item effects, or unique passive bonuses. The Lore of Artificers is a unique Yellow Gem only obtainable via the '???' reward option.
- Purple Gems: Activate during Fury mode, providing powerful temporary buffs.
- Green Gems: Often related to defense, HP, or regeneration.
- Orange Gems: Can provide various resistances or status effect immunities.
- Impure Gems: Generally have negative effects or highly situational benefits.
Gem Fusion:
At the Bomb Bros R&D store, you can fuse gems. Fusion combines two or more gems to create a new, often more powerful gem, or to transfer specific properties. The Bomb Brothers will guide you through the process. Experiment with different combinations to discover potent new effects. Gems can be bought and sold at Bomb Bros R&D, though selling them only yields a fifth of their purchase price. Multiplayer sessions also offer unique gems not found in single-player mode.