This project includes analysis of the Mars Pathfinder soil data (spectral, chemical and magnetic) together with analog materials and the products of laboratory alteration experiments in order to describe possible mechanisms for the formation of soil, duricrust and rock coatings on Mars. Soil analog mixtures have been prepared, characterized and tested through wet/dry cycling experiments for changes in binding and spectroscopic properties that are related to what could be expected for duricrusts on Mars. The smectite-based mixture exhibited significantly greater changes (1) in its binding properties throughout the wet/dry cycling experiments than did the palagonite-based mixture, and (2) in its spectral properties following grinding and resieving of the hardened material than did the palagonite-based mixture.