Ivory Tower Wizard Janssen:
Figured you'd help, so I'll tell you what to do.
You'll find a Hidden Crusher made by the wizards of Ivory Tower on Cruma Tower: Underground Lv. 1.
This powerful magical device can destroy any magical object. But, it was hidden to prevent anyone from misusing it, and since it requires magic to destroy something, it could self-destruct by consuming any residual magic left on it.
If the crusher is destroyed before all the fragments are, you'll need to find another one.
After the fragments have been destroyed, bring back 20 Normal Fragment Dust.