This article is about the type of sedimentary rock. For the work by Archimedes, see The Sand Reckoner.
Psammite (Greekpsammos, sand) is a general term for sandstone. It is equivalent to the Latin-derived term arenite. Also, it is commonly used in various publications to describe a metamorphosed sedimentary rock with a dominantly sandstone protolith. In Europe, this term was formerly used for a fine-grained, fissile, clayey sandstone. Pettijohn  gives the following descriptive terms based on grain size, avoiding the use of terms such as "clay" or "argillaceous", which carry an implication of chemical composition: