How to apply/remove sockets
To apply a socket, summon your Black Spirit and click “Socket”. Next right-click the piece of equipment and the sockets you would like to use. Sockets have a chance of breaking when you die.
There are two ways you can remove sockets from your equipment. The first way will destroy the crystal. To do this summon your Black Spirit and click “Sockets”. Next, right-click the crystal that is currently on your equipment and click “Enter” to confirm.
The other way you can remove sockets requires a pearl store item but will not destroy the crystal. The item is called “Black Spirit Essence” and can be bought for 200 pearls by pressing “F3” then going to the “Function” tab. Once you have the item, go to the blacksmith and click “Extraction” then “Extract Crystal”. Right-click your piece of equipment and the item then click “Extract”.
List of Crystal Sockets