"Yes, Seekin?" Larkin said.
The Martian smiled. A little uncertainly he pushed the list across the counter.
"I do not need all of these for me and mine, but the ground is prepared and ready, and if I have these minerals I will be able to grow more than I need. Then there will be something over for someone else to use in the time of scarcity." His voice was as soft as a breeze, there was no hint of a demand in it. But there was a pleading in the eyes that looked at the human.
Larkin took the list. Rapidly translating the Martian script, he saw that Seekin wanted approximately five grams of powdered cobalt, copper, boron, manganese, with traces of iron, zinc, and calcium. Phosphorus also was included and a smattering of trace elements.
The trader went quickly to the bins and filled the order, tossing the correct amount of the powdered elements into the agitator for mixing. He spun the crank of the agitator and the machine hummed softly. The powdered minerals poured from the spout. He bagged the mixture. His practiced eye told him that the cost of these minerals, delivered here on Mars, was approximately two hundred dollars.
The Martian's eyes became fixed longingly on the little bag when Larkin laid it on the counter. There was an eagerness in the eyes that was almost as strong as the eagerness for life itself. But there was uncertainty too. He fumbled with the opal.
"This is all we have," he said.
Larkin grinned. "It's odd, isn't it, how things achieve a balance? Those minerals come to just exactly the price of this jewel."
A glow lit the Martian's face. "Do you mean it?"
"Of course."