I need help, I once read this fantasy book when i was a kid and I want to read it again but I can’t figure out what the title was.

Hey Reddit, so I need help. I once read this book about a girl living in a poor rural miners town that mines this rock for the country. Then one day there’s an announcement of some sort that the crown prince is looking for a bride chosen from their town?
All eligible girls are taken down the mountain a bit to learn manners, how to read, write, etc. the MC and an outsider that is brought to the town make plans to make the prince notice the outsider. I think there was a ball that got taken hostage and the men look for the girl chosen by the prince. But each one says that they’re the chosen bride, or something? The girls later find out the stone the town mines is very valuable and they start to charge the merchants for the proper costs and then live happily ever after?
Idk for sure but I’m going nuts trying to figure this out. If someone recognizes this story can you please let me know the title?

by DarkProfessional9601