illite

American  

[il-ahyt] / ˈɪl aɪt /

noun

1. any of a group of clay minerals, hydrous potassium aluminosilicates, characterized by a three-layer micalike structure and a gray, light green, or yellowish-brown color.

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illite British  

/ ˈɪlaɪt /

noun

1. a clay mineral of the mica group, found in shales and mudstones. Crystal structure: monoclinic. Formula: K 1–1.5 Al 4 (Si 6.5–7 Al 1–1.5 O 20 )(OH) 4

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Other Word Forms

• illitic adjective

Etymology

Origin of illite

First recorded in 1937; Ill(inois) ² ( def. ) + -ite ¹