Jeweler
Rare7.1%GrindOptionalAnywhere
Collect 10 Bittergems.
Collect 10 Bittergems, cumulative. Bittergems are rare purple gemstones hidden in the rock - you'll spot the distinctive sparkle occasionally while mining. Dig them out whenever you see one; 10 trickle in over time. Keep your eyes (and Bosco's laser) peeled for the glitter.