Know all about Siltstone and Greywacke properties here. All properties of rocks are important as they define the type of rock and its application. Siltstone and Greywacke belong to Sedimentary Rocks.Texture of Siltstone is Clastic whereas that of Greywacke is Clastic. Siltstone appears Rough and Greywacke appears Dull. The luster of Siltstone and Greywacke is dull. Siltstone is available in brown, red, reddish brown colors whereas Greywacke is available in beige, black, brown, colourless, cream, dark brown, green, grey, light green, light to dark grey, pink, red, white, yellow colors. The commercial uses of Siltstone are raw material for the manufacture of mortar, soil conditioner and that of Greywacke are as armour rock for sea walls, petroleum reservoirs, sea defence, tombstones.