• WordNet 3.6
    • n argillite a sedimentary rock differing from shale in being bound by silica and from slate in having no slate cleavages
    • ***
Webster's Revised Unabridged Dictionary
    • n Argillite (Min) Argillaceous schist or slate; clay slate. Its colors is bluish or blackish gray, sometimes greenish gray, brownish red, etc.
    • ***
Century Dictionary and Cyclopedia
    • n argillite Argillaceous schist or slate; clay slate (which see, under clay).
    • ***


Webster's Revised Unabridged Dictionary
Gr. clay + -lite,


In literature:

They are always formed of argillite.
"The Prehistoric World" by E. A. Allen
Slate is, as we know, merely a variety of argillite.
"Scientific American Supplement, No. 1157, March 5, 1898" by Various
Next above the Altyn lies thirty-four hundred feet of Appekunny argillite, or dull-green shale.
"The Book of the National Parks" by Robert Sterling Yard
Near the upper end of the camp, Avalanche Creek has cut a deep, narrow gorge through brilliant red argillite.
"Glacier National Park [Montana]" by United States Dept. of the Interior

In news:

Haida Argillite Figure, ca 1860 PBS.
It turns out arrowheads can be made of argillite, chalcedony, chert/flint, diorite, hematite, jasper, rhyolite, siltstone, crystal quartz, quartz, and quartzite.
ARGILLITE — Until the last few years of his life, Bill Kelly's best friends rarely ever heard him talk about being a soldier during the Battle of the Bulge .
ARGILLITE — A stalled proposal to expand horse trails at Greenbo Lake State Resort Park may get under way soon thanks to a donation by a local industry.