American Society for Testing and Materials (ASTM). Current edition approved Jan. 1, 2005. Published January 2005. Originally approved in 1952. Last previous edition approved in 2004 as C 294 – 04. 10 p. This descriptive nomenclature provides brief descriptions of some of the more commonly occurring, or more important, natural and artificial materials of which mineral aggregates are composed. The descriptions provide a basis for understanding these terms as applied to concrete aggregates. When appropriate, brief observations regarding the potential effects of using the natural and artificial materials in concrete are discussed.