Marsport, the largest—if you excluded the prospecting encampments within a hundred-mile radius of the place—city on the Planet, had grown fast, from the time of its founding in 2014. Originally simply a mining site for the Tri-Planet Refining Corporation, it had spread backward from the area of the original mines in a rough circle, beginning with the monotonous quonset huts of the miners, and modulating in its move toward the perimeter to smart iron-and-adobe structures. Some of these, thanks to the less-than-half Earth's normal gravity, as high as fifteen stories.
The planet, barely half the diameter of Earth and a tenth of Earth's mass, was a minerologist's paradise. The rusty red sands of the Martian desert were almost pure ferrous oxide, a source of both iron for the profitable refineries and oxygen for the inhabitants of Marsport.
Going Los Angeles one ridge better, Marsport was completely circumscribed by high crimson hills, and this natural bowl formation, plus oxygen's heavier-than-air-density, allowed the city to be filled with breathable atmosphere, much as tobacco smoke can lie surging gently within an ashtray if the air in a room is still. This made planetary wind-storms a hazard.
Outside the hills, of course, the air was thin, cold and barely able to support life, being comparable to the biting cold air atop Mount Everest. Human lungs could not breathe it for long without freezing. Naturally, there was a high casualty rate amongst the prospectors, despite their pressurized metal huts and oxygen masks. But uranium, as it had been since the advent of the atomic age, was enormously well-paying to the one miner in twenty to find any in Mars' body breaking hinterlands with its roasting dry heat of day and blood-freezing cold by night.
And then there was parabolite.
This mineral, found in abundance beneath the Martian sands, was, theoretically, worth ten times its weight in gold to the people who might mine it. I say theoretically, because no one had as yet found a way of getting any ore. Paradoxically, the feature which made parabolite so vitally desired was the same feature which prevented anyone from mining it: it was totally indestructible.
The name had been given it by the scientists who studied the three solitary fragments of it found small enough for shipping back to Earth. There was just no way of chipping a piece loose for analysis. The name was due to the oddly shaped molecules which made up this mineral. All of them seemed to be joined atomically into perfect parabolas, no matter which way you came at them. Which meant, in effect, that when anything was brought to bear against the substance, pressure which struck one end of the parabolically curved molecules was retransmitted by the other end, back to the thing putting pressure on it. Result: it "hit back" with a violence equal to that applied to it, and sustained no damage whatsoever to itself. Chemicals were tried when pickaxes had failed, but the substance was inert. It gave no sign of reacting either to hydrofluoric acid, which could eat its way through glass, or to aqua regia, which could eat through anything else.
They even tried using the collapsers on it. These deadly weapons, which worked by the simple process of killing the attraction between the protons and electrons, could, in the briefest time, reduce anything to less than dust. The electrons spun away in a blinding blue-white flash, and the stripped-down protons, being less than atomic in size, fell silently down into the heart of the planet, leaving a virtual nothingness where the object had been.
But on parabolite, even these mighty weapons were useless. Oh, they had found that training a battery of them on a chunk of parabolite, for a period of days, with an enormous drain of power keeping the weapons firing continuously, did get results. The overall mass of the chunk was reduced by one-millionth of a gram. Which was less than useless, because not only was that amount completely impractical to obtain, but it was not even obtained, thanks to the collapsers' destructive potency. It was merely destroyed.
And so, vast acres of this fortune-making mineral lay all about the planet, as common as sandstone was on Earth. And no one had any idea of how to get any of it, not even the natives.