phyllite

American  

[fil-ahyt] / ˈfɪl aɪt /

noun

1. a slaty rock, the cleavage planes of which have a luster imparted by minute scales of mica.

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phyllite British  

/ fɪˈlɪtɪk, ˈfɪlaɪt /

noun

1. a compact lustrous metamorphic rock, rich in mica, derived from a shale or other clay-rich rock

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phyllite Scientific  

/ fĭl′īt′ /

1. A green, gray, or red metamorphic rock, similar to slate but often having a wavy surface and a distinctive luster imparted by the presence of mica.

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Other Word Forms

Derived Forms

• phyllitic
  adjective

Etymology

Origin of phyllite

First recorded in 1820–30; phyll- + -ite ¹

Example Sentences

Two years ago, I scrambled into a six-foot-deep soil pit dug into this hillside to examine the crumbling phyllite rock just below the topsoil.

From Washington Post • May 10, 2019

The rock sequence is sedimentary rock, slate, phyllite, schist, gneiss, migmatite, and granite.

From Textbooks • Jan. 1, 2017

The sequence slate → phyllite → schist → gneiss illustrates an increasing metamorphic grade.

From Textbooks • Jan. 1, 2017

Where slate is typically planar, phyllite can form in wavy layers.

From Textbooks • Jan. 1, 2015

All gradations between it and phyllite may be traced, and in many cases we may prove it due to the metamorphism of slates and shales.

From The Elements of Geology by Norton, William Harmon