Know all about Siltstone and Gneiss properties here. All properties of rocks are important as they define the type of rock and its application. Siltstone belongs to Sedimentary Rocks while Gneiss belongs to Metamorphic Rocks.Texture of Siltstone is Clastic whereas that of Gneiss is Banded, Foliated, Platy. Siltstone appears Rough and Gneiss appears Foliated. The luster of Siltstone and Gneiss is dull. Siltstone is available in brown, red, reddish brown colors whereas Gneiss is available in black, brown, pink, red, white colors. The commercial uses of Siltstone are raw material for the manufacture of mortar, soil conditioner and that of Gneiss are cemetery markers, jewelry, tombstones, used in aquariums.