Fantasy steampunk-esque book, main character works in a mine that digs crystals made from lightning out of the ground, goes adventuring with a group and at some point visits ruins in the sky?

[Jarret]

Cant remember much abput this book, I read it in middle school and really enjoyed it.

[Gillian]

What year(s) were middle school? Was it new then? Was the MC male or female? Were there non-humans? Were the ruins on a cloud or a floating rock, or what?

Was the book aimed at kids, teens or adults? Do you remember anything about the cover? Any or all that you can remember may trigger someone else's memories...

[Jarret]

MC was male, there were elves, I believe the book was aimed towards teens.

[Jarret]

The whole ruins in the sky part is very hazy, even a chance it didn't happen.