Know all about Siltstone and Argillite properties here. All properties of rocks are important as they define the type of rock and its application. Siltstone and Argillite belong to Sedimentary Rocks.Texture of Siltstone is Clastic whereas that of Argillite is Clastic, Polished. Siltstone appears Rough and Argillite appears Rough and Dull. The luster of Siltstone is dull while that of Argillite is waxy and dull. Siltstone is available in brown, red, reddish brown colors whereas Argillite is available in dark grey to black, pink, red, white colors. The commercial uses of Siltstone are raw material for the manufacture of mortar, soil conditioner and that of Argillite are fire resistant, used to manufracture paperweights and bookends.