Have you ever wanted to remove a crystal from a piece of equipment without destroying it? It is possible with the Black Spirit Essence or Crystal Extraction Tool:
Black Spirit Essence can be purchased in the Pearl Shop.
The Crystal Extraction Tool can be obtained during certain in-game events.
You will need to visit a Blacksmith to use it. You will not be able to use the Essence/Tool if you extract a crystal through your Black Spirit.
Once you've pressed the "Extraction" button, choose the "Extract Crystal" option":
In the next window, you can select the piece of gear where you wish to extract the crystal from.
Attention: Make sure to use the Black Spirit Essence/Crystal Extraction choosing one of the options in the bottom right corner.
The Black Spirit Essence / Crystal Extraction Tool will not be automatically used unless you choose it.
After this, press the "Extract" button and you will find the crystal and gear intact in your inventory.