Bath bombs = More blue gems. Or a gem growth machinery on the moon.

[Frosty_Mentos]

Considering that ruins provide most red gems and purples you'd need, the biggest rarity there are blue ones. So suggestion idea there to propose is that you could get a fairly hefty amount of blue ones when using bath bombs.

Or could induce gem growth in the moon pools using some sort of Wagstaff inspired machinery, where you could fuel them with bath bombs and they thumper the glass and gems off the pool. They'll refill, turn to glass, repeat. Would need player maintenance in order to produce more. Kinda like how Tar Extractors work in Shipwrecked in a way.