Know all about Siltstone and Phonolite properties here. All properties of rocks are important as they define the type of rock and its application. Siltstone belongs to Sedimentary Rocks while Phonolite belongs to Igneous Rocks.Texture of Siltstone is Clastic whereas that of Phonolite is Granular. Siltstone appears Rough and Phonolite appears Banded and Foilated. The luster of Siltstone is dull while that of Phonolite is greasy to dull. Siltstone is available in brown, red, reddish brown colors whereas Phonolite is available in brown, buff, cream, green, grey, pink, white colors. The commercial uses of Siltstone are raw material for the manufacture of mortar, soil conditioner and that of Phonolite are cemetery markers, creating artwork.