When cast, the spell altered the molecular structure of an object, increasing its density, making it harder. The spell was able to alter up to 10 ft³ (0.28 m³) of material at a time. The hardiness and the amount of material affected was determined by the caster's skill level. The spell did not affect an objects physical state nor it's ability to alter states. For example, if cast onto a sheet of ice, the ice would still melt normally when exposed to head.