From Granblue Fantasy Wiki
Weapon Stones are rare materials needed for advanced crafting. Players typically get them from reducing unneeded and weapons.
|Uncap Celestial weapons to 4★||20|
|Uncap Omega weapons to 4★||200|
|Uncap Showdown SSR weapons to 4★||60|
|Rebuild Class Champion Weapons||256 (|
50First time only)
|Change a Class Champion Weapon's element||512 (|
150First time only)
|Uncap Xeno Weapons to 4★||300|
|Uncap Trade Moon Weapons to 4★||300|
|Uncap Premium Gala Weapons to 4★||300|
|Uncap Premium Draw Weapons to 4★||200|
|Uncap Silver Relic||300|
|Create an Ultima Weapon||500|
Weapon stones are primarily obtained from reducing weapons.