Question

Can compounds found in concrete leach into soil against gravity?

Answer 1

The problem is sorting. Ergo, unless you bring your separator with you, the best areas for finding naturally sorted materials are in outflows such as found in Candor Chasma. Semi-translucent larger grains of quartz-rich phenocrysts might be found in useful quantities. Fusing these with a solar kiln would produce a brick of about 0.125 meters thick that would both shield from the rain of radiation and pass some of the weak Martian sunlight, easing the circadian rhythm of colonists. Time to temperature (1700 degrees C) still makes production slow. And the loaders and other equipment need to be transported and successfully landed.