 Val and Ron's geiger is programmed to identify:
THE HUNTED HEROES By ROBERT SILVERBERG The planet itself was tough enough—barren, desolate, forbidding; enough to stop the most adventurous and dedicated. I reached over and turned up the pressure on her oxymask to make things a little easier for her. Nothing but what had stopped us could stop a sandcat: sand in the delicate mechanism of the atomic engine. When Val's tired and overwrought there's no sense in arguing with her. We had wandered fruitlessly over the red sands all day, both of us listening for the clicks of the counter. And the geigers had been obstinately hushed all day, except for their constant undercurrent of meaningless noises. We knew the pay was poor, but we had felt it a sort of obligation, something we could do as individuals to keep the industries of radioactives-starved Earth going. 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. "What'samatter, Ron?" I watched her, sleeping peacefully, a wayward lock of her soft blonde hair trailing down over one eyebrow, and it seemed hard to believe that we'd exchanged Earth and all it held for us for the raw, untamed struggle that was Mars. The Geig Corps preferred married couples, working in teams. It had been spun on us only a short time ago, I realized. He wore an outmoded, bulky spacesuit and a fishbowl helmet, all but the face area opaque. The oxygen cannisters weren't attached to his back as expected, though. 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. He reached for the tanglegun, flipped the little switch on its side to MELT, and shot a stream of watery fluid over our legs, keeping the blaster trained on us all the while. Val and I helped each other to our feet as best we could, considering our arms were still tightly bound against the sides of our oxysuits. Earth needed radioactives, and the only way to get them was to get out and look. The great atomic wars of the late 20th Century had used up much of the supply, but the amount used to blow up half the great cities of the world hardly compared with the amount we needed to put them back together again.
 Uranium
 The Sandcat  The Dome  Uranium  humans