Magicite

Magicite are a type of magical stones that appear in several Final Fantasy games. While their debut was in Final Fantasy II, Magicites are most prominent Final Fantasy VI, in which they are the leftover remains of an Esper.

Final Fantasy VI
In Final Fantasy VI, Magicites are sought after by Kefka and the Gestahlian Empire. When an Esper dies, it is converted into Magicite, although its spirit remains intact. The party collects Magicites throughout their journey. The player can equip a Magicite to individual party members from the menu's option. This way, if a party member has enough MP, they can briefly summon an Esper from the Magicite, although this can only be done once per battle.

Equipping a Magicite to a party member gives them a chance to learn new magic spells. After each battle, the party member gains AP, which add toward a percentage for each of the spells. Once a spell has reached 100%, the character learns that spell. Furthermore, some Magicites grant a level up bonus to certain stats to the corresponding party member.

During their journey, the party also find Magicite Shards, which are single-use items that summon a random Esper during battle.

Final Fantasy Crystal Chronicles
In Final Fantasy Crystal Chronicles, Magicite are large, colored spheres that are found in every level. They grant the characters magical abilities, but disappear at the end of each stage.