Just realized that I should have put saltpeter in sandstone, not in granite. Reasons:
- Sandstone is shallow in the game, which matches shallow location of saltpeter
- It would be the first mineral to be found in sandstone, increasing game variation
- In nature the mineral is found in arid areas only, and sandstone mostly exists in deserts in Survivalcraft – another match
Too late to fix for 1.10, but will amend in 1.11.
1.10 still in certification.