Artifacts

Artifacts are objects found underground worth cash, much like minerals, but with a few differences.


 * They are much rarer - you may need to dig 1000 ft just to find 1 or 2 of them.
 * Their rarity is not strictly correlated with depth - high-value artifacts can be found near the surface.
 * They do not need to be sold - cash is granted when artifacts are drilled into, and they do not go into the inventory.
 * They always give 500000 points each.