See Spiritbond for more information about obtaining materia.

To unlock materia melding, the prerequisite quest Waking the Spirit must be completed. To meld, one must have (i) the equipment being melded with an available "slot" for melding; (ii) the materia to be melded; (iii) a catalyst (such as Grade 3 Carbonized Matter) of equal or higher grade; and (iv) sufficient levels in the applicable Disciples of the Hand job. If one does not meet the level requirement, it is also possible to Request Meld from a player who does or use the services of special NPCs to attach the materia. Additional restrictions on how many materia can be melded, and how high a certain stat can be augmented, depend on the gear being melded itself. The in-game melding screen will document the chance of success (dependent on the grade of materia and how many melds the item already has), and whether, if successful, the item will accept the proposed stat augmentation.