The specifications for aggregates for use in hydraulic-cement concrete should be different to the extent that the requirements for the concrete impose different requirements or require different levels of relevant properties of the aggregate. If satisfactory local practice either requires a more severe restriction or permits variance from a restriction of a general specification, then these differences should exist. It says, in ASTM C 33 (and has done so for many years): This specification is regarded as adequate to ensure satisfactory materials for most concrete. It is recognized that, for certain work or in certain regions, it may be either more or less restrictive than needed. For example, where aesthetics are important, more restrictive limits may be considered regarding impurities that would stain the concrete surface. The specifier should ascertain that aggregates specified are or can be made available in the area of the work, with regard to grading, physical, or chemical properties, or combination thereof.