Thrawn knows that the Empire mines those crystals, including for a certain Project Stardust. He's not about to indulge that particular bit of future history to her at the moment. Interesting that those crystals are what powers the lightsabers.

"I don't see why not." Thrawn holds out his hand and a glowing dagger appears in his hand. "I have not tried to replicate a lightsaber, but theoretically, it should be possible." The dagger fades from existence.

"There was a Jedi here, and he had a lightsaber, but he has since left and taken his weapon with him. A shame, since we could have used it as a baseline."