"It's a particular kind of stone you'd only really find in my world. I had to improvise a substitute, and supercharge some quartz with magic. That was pretty draining work."

Good thing coffee restores MP, then. She takes a long sip,and gestures to the last, faintly glowing spike of crystal on the worktable nearby.

"The result SHOULD handle the intense flux shifts inherent in time travel. Or it could, you know, blow up. But by my calculations, that's a very remote possibility."