Crystal weapons can be enchanted.
If you use FF4 and cannot view the ZohoSheet online calculators, there is now a workaround. Click here!
In order to input your data, click the "Click to Edit" button. Afterwards, specify whether you are two-handing
the weapon (1) or not (0). Then, plug in the stat values you wish to test.
Note: Should you accidentally delete something important, simply reload the page to restart.
I apologize but this edit method is the best I can find currently.