Know all about Siltstone and Gabbro properties here. All properties of rocks are important as they define the type of rock and its application. Siltstone belongs to Sedimentary Rocks while Gabbro belongs to Igneous Rocks.Texture of Siltstone is Clastic whereas that of Gabbro is Phaneritic. Siltstone appears Rough and Gabbro appears Veined and Shiny. The luster of Siltstone is dull while that of Gabbro is not available. Siltstone is available in brown, red, reddish brown colors whereas Gabbro 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 Gabbro are cemetery markers, commemorative tablets, laboratory bench tops, jewelry, sea defence, tombstones.