I have hit level 15 in jewelcraft and I'm looking for a good way to raise it further (up to 25-30 range for now). Is there a way to grind it up effectively using only one resource? I've been doing cut gems, but it's really slow going as I'm at the top end of the level 1 stuff (so little xp), but not high enough to do the next level efficiently yet.

Any advice would be appreciated