 Val and Ron's geiger is programmed to identify:
The planet itself was tough enough—barren, desolate, forbidding; enough to stop the most adventurous and dedicated. And the geigers had been obstinately hushed all day, except for their constant undercurrent of meaningless noises. The geiger kept up a fairly steady click-pattern, but never broke into that sudden explosive tumult that meant we had found pay-dirt. I stopped, slipped out of the geiger harness, and lowered myself ponderously to the ground. He wore an outmoded, bulky spacesuit and a fishbowl helmet, all but the face area opaque. He was holding in his left hand the tanglegun with which he had entrapped us, and a very efficient-looking blaster was in his right.
 Uranium
 The Sandcat  The Dome  Uranium  humans