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