from The American Heritage® Dictionary of the English Language, 4th Edition

  • n. A metamorphic rock, intermediate between shale and slate, that does not possess true slaty cleavage.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • n. A fine-grained sedimentary rock, intermediate between shale and slate, sometimes used as a building material

from the GNU version of the Collaborative International Dictionary of English

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

from The Century Dictionary and Cyclopedia

  • n. Argillaceous schist or slate; clay slate (which see, under clay).

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

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


Latin argilla, argil; see argil + -ite1.
(American Heritage® Dictionary of the English Language, Fourth Edition)


  • Indeed, the art of the argillite is a story of resistance.

    Archive 2009-03-01

  • For years there have been "argillite" replicas of the Haida carvings - made who knows where?

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  • Soils from argillite are clayey, poorly drained, and have hardpans in lower horizons.

    Ecoregions of New Jersey (EPA)

  • On poorly drained, clayey soils with hardpans that were derived from argillite, native vegetation is a mosaic of red maple, swamp hardwoods, and mixed oaks, including pin oak.

    Ecoregions of New Jersey (EPA)

  • Ecoregion 84d is lithologically distinct from the reddish shale, sandstone, argillite, and siltstone of the neighboring Triassic Lowlands (64a).

    Ecoregions of New Jersey (EPA)

  • In New Jersey, Triassic brownish red, shale, sandstone, and argillite are extensive; these sedimentary rocks are much less resistant to erosion than the metamorphic crystalline rocks that form the core of the adjacent Northeastern Highlands (58).

    Ecoregions of New Jersey (EPA)

  • Portions are underlain by argillite and quartzite; they have substantially different water quality and fish assemblages than other areas underlain by limestone and dolomite.

    Ecoregions of Montana (EPA)

  • The rocks of the North Island's rugged axial ranges are older, brittle, sedimentary rocks (greywacke and argillite) that broke up into a series of blocks (or ranges) along major fault lines as they were uplifted.

    Northland temperate forests

  • The soils of Ecoregion 64a were derived from Triassic sandstone, shale, siltstone, and argillite of the Brunswick, Stockton, Lockatong, Gettysburg, and New Oxford formations; lithology is distinct from the metamorphic rocks of the surrounding portions of the Piedmont.

    Ecoregions of Delaware, Maryland, Pennsylvania, Virginia, and West Virginia (EPA)

  • It is underlain by quartzite and argillite; the lithologic mosaic and related slope stability and water quality issues are unlike those of Ecoregion 16k.

    Ecoregions of Idaho (EPA)

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