Alien crystals come in two variations; small alien crystals and large alien crystals, possibly a form of alien currency. They are only found aboard Mothership Zeta on some aliens, lying on some tables or shelves where they are especially hidden among the alien artifacts that cannot be picked up. Most quantities for both variants are found in the hangar and robot assembly.
They are weightless, and have values of 10 and 20 bottle caps respectively. They have no other use besides as trade items, Rock-It Launcher ammunition, or as a decoration.
- 39 small/large crystals in the robot assembly
- 36 small/large crystals in the hangar
- 13 small/large crystals in the living quarters
- 7 small crystals in the observation deck
- 7 small crystals in the cryo lab
- 7 small crystals in the engineering core
- 7 large crystals in the weapons lab