Know all about Siltstone and Theralite properties here. All properties of rocks are important as they define the type of rock and its application. Siltstone belongs to Sedimentary Rocks while Theralite belongs to Igneous Rocks.Texture of Siltstone is Clastic whereas that of Theralite is Phaneritic. Siltstone appears Rough and Theralite appears Veined and Shiny. The luster of Siltstone is dull while that of Theralite is waxy and dull. Siltstone is available in brown, red, reddish brown colors whereas Theralite is available in dark grey to black colors. The commercial uses of Siltstone are raw material for the manufacture of mortar, soil conditioner and that of Theralite are cemetery markers, commemorative tablets, creating artwork, laboratory bench tops, jewelry, sea defence, tombstones.