Quasicrystals are materials with unusual atomic structure, coupled with unusual physical properties. Surface properties are particularly important, because most proposed applications quasicrystals involve low-dimensional solidsscoatings, thin films, precipitates, or compositesswhere the ratio of surface area to volume is high. Perhaps the most fundamental surface property is chemical reactivity. Studies under various environmental conditions suggest that quasicrystals are relatively unreactive and/ or corrosion-resistant