Amorphous derivates prepared by aqueous reaction of various aluminosilicate clay minerals with concentrated KF solution at 80-110 degrees C were studied for their gas adsorption properties. The four clay minerals studied are halloysite, a well-crystallized kaolinite, a poorly crystallized kaolinite, and a montmorillonite. The gases tested are N 2 , O 2 , CH 4 , CO, CO 2 , and C 2 H 2 . The kaolin-group mineral derivatives are characterized by substantial reduction in particle size, high specific surface, and significant selectivity towards CO 2 and C 2 H 2 relative to the other gases. The montmorillonite derivative shows no increase in adsorption over the starting material, however, for all the materials high adsorption of CO 2 and C 2 H 2 was observed. Levels of gas adsorption and gas adsorption ratios are comparable to pillared clays.