Gives materials, tolerances and minimum performance levels for cast stone such as sills and copings (see BS 5642), lintels, mullions, pier caps, ashlar, cladding units, balusters, etc. Excludes reconstructed stone masonry units as specified in BS 6457, i.e. units manufactured with aggregate and cementitious binder and intended to resemble, and to be used for similar purposes as natural stone. Includes sampling, marking, determination of compressive strength, drying shrinkage and initial surface absorption.