Gem deposits.

[Ashbery76]

They seem to give a farming bonus and farmers but nothing else?

[Zaimat]

Gold +25% or Gem deposits give a +50% tax income (based on population workforce) shown in the Government building.

I'll be adding some tooltips to break down the planetary income.

[Zaimat]

I've also added a straight-up base bonus component to the gold/gem deposits. +250mc / +500mc per turn once it's upgraded to a colony.