The schist used in traditional masonry constructions, extracted from the construction site, provides them traits that distinguish and characterize the local architecture. The understanding of the mechanical behaviour of schist constructions requires a detailed knowledge of the schist as a material. This study aims at filling the gap in scientific knowledge by characterizing the schist as a construction material. This paper provides a characterization of schist's from five distinct areas of Portugal. Tests have been carried out to characterize schist's regarding porosity, density and mechanical strength. Results indicate that it is possible to apply schist as a construction material with a higher degree of confidence, by suiting the schist type to the physicochemical and mechanical needs of the construction; furthermore, it is possible to evaluate the existing schist constructions according to the schist type used, allowing less intrusive and more appropriate forms of intervention.