When following the discussion about gem generators, it struck me that one solution to this problem could be to make them summons.
- They could be immobile with 1hp so would be fragile in war.
- Hammers wouldn´t help in summoning them
- They could be assigned a hefty upkeep (like 50g per turn) to prevent hoarding
The downside is that while they could still be multipath, they would only cost gems of one type. Like 20 water for clams (aquatic?), 40 blood slaves for stones and 15 nature for fetishes (spreads disease in province?).
Opinions? Is it possible?