argillite

n. any rock made up of layers of clay sediment

"Argillite" may also refer to Argillite, Kentucky. An argillite (IPA: ) is a fine-grained sedimentary rock composed predominantly of indurated clay particles. Argillites are basically lithified muds and oozes. They contain variable amounts of silt-sized particles. The argillites grade into shale when the fissile layering typical of shale is developed. Another name for poorly lithified argillites is mudstone. These rocks, although variable in composition, are typically high in aluminium and silica with variable alkali and alkaline earth cations. The term pelitic or pelite is often applied to these sediments and rocks.  Metamorphism of argillites produces slate, phyllite, and pelitic schist.
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Noun
1. a sedimentary rock differing from shale in being bound by silica and from slate in having no slate cleavages
(hypernym) sedimentary rock

n. oil shales, layers of condensed oil

(n.)
Argillaceous schist or slate; clay slate. Its colors is bluish or blackish gray, sometimes greenish gray, brownish red, etc.