Know all about Siltstone and Variolite properties here. All properties of rocks are important as they define the type of rock and its application. Siltstone belongs to Sedimentary Rocks while Variolite belongs to Igneous Rocks.Texture of Siltstone is Clastic whereas that of Variolite is Glassy, Massive, Porphyritic, Scoriaceous, Vesicular. Siltstone appears Rough and Variolite appears Dull and Soft. The luster of Siltstone is dull while that of Variolite is not available. Siltstone is available in brown, red, reddish brown colors whereas Variolite is available in black, brown, light to dark grey colors. The commercial uses of Siltstone are raw material for the manufacture of mortar, soil conditioner and that of Variolite are cemetery markers, creating artwork.