OreMania

Cute game, reminiscent of the mining mini game in the gen Pokemon gen 4 underground and just as satisfying.
Tap rocks, collect gems, sell gems for upgrades, display gems in your exhibit. You can get all the achievements real quick if that's what you care about.

Surprisingly quick fun game with some fun info about gemstones, honestly played it for pokemon underground nostalgia.

Meh. 100% achievements in 49mins. The upgrading/incrementalism is short and meh. The achievements and many parts of the game are still in Japanese, and bad English elsewhere. Don't really need the language though.