Rocks are naturally occurring solids which are composed of minerals & have been used by humans since ages. From Stone Age, rocks are used for various purposes. Also, the metals and minerals found in rock play an important role in our life. Get to know all the Argillite Uses. We have provided you with all information about Argillite rock here. Argillites are highly compact sedimentary or slightly metamorphosed rocks that consist largely or wholly of particles of clay or silt but lack the fissility of shale or the cleavage characteristic of slate. Argillite is available in dark grey to black, pink, red, white colors. The streak of a rock is the color of powder produced when it is dragged across an unweathered surface. The streak of Argillite is white to grey. Get to know more about Argillite rock and characteristics of Argillite rock in the next sections.