illite

[ il-ahyt ]

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.

illite

/ 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

Other Words From

• il·lit·ic [ih-, lit, -ik], adjective

Word History and Origins

Origin of illite¹

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

Word History and Origins

Origin of illite¹

C20: named after Illinois , where it was first found