An another crystal income with limitations.
- Geogolists can find crystal mine. (Find crystal deposit: 8hours, like granite)
- Only one crystal mine would be on your island.
- Crystal mine contains only 7 crystal
- Production time 1 crystal/24 hours.
- Crystal mine upgradeable and refillabe only with gems (10 crystal - 290 gems same calculation like in The excelsior airship)
- Crystal mine buffable
With 5x buffs, this means +35crystals / week.
This is not too much, but would make crystal economy unbalanced (see [Dev Blog] Excelsior) problems with gems. If you have too much crystals you can spend too much on letters, and you can earn too much free gems. If they can fix that balance problem (maybe limitation on gem income / week) then that crystal mine would be more powerful.