argillite Meaning, Definition & Usage

  1. noun a sedimentary rock differing from shale in being bound by silica and from slate in having no slate cleavages

WordNet

Ar"gil*lite noun
Etymology
Gr. clay + -lite.
Definitions
  1. (Min.) Argillaceous schist or slate; clay slate. Its colors is bluish or blackish gray, sometimes greenish gray, brownish red, etc. -- Ar`gil*lit"ic, a.

Webster 1913