Psephite

 Psephite (Greek: psephos, "pebble") is either a sediment or sedimentary rock composed of fragments that are coarser than sand and which are enclosed in a matrix that varies in kind and amount. It is equivalent to a rudite. Shingle, gravel, breccia, and especially conglomerate, would all be considered psephites. It is equivalent to the Latin-derived term rudite. Psephite is more commonly used for a metamorphosed rudite.^[1]

Pettijohn ^[2] 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:

Descriptive size terms

Texture	Common	Greek	Latin
Coarse	gravel(ly)	psephite (psephitic)	rudite (rudaceous)
Medium	sand(y)	psammite (psammitic)	arenite (arenaceous)
Fine	clay(ey)	pelite (pelitic)	lutite (lutaceous)

This article uses material from the Wikipedia article  Metasyntactic variable, which is released under the  Creative Commons Attribution-ShareAlike 3.0 Unported License.