Know all about Siltstone and Rhomb Porphyry properties here. All properties of rocks are important as they define the type of rock and its application. Siltstone belongs to Sedimentary Rocks while Rhomb Porphyry belongs to Igneous Rocks.Texture of Siltstone is Clastic whereas that of Rhomb Porphyry is Aphanitic to Porphyritic. Siltstone appears Rough and Rhomb Porphyry appears Rough. The luster of Siltstone is dull while that of Rhomb Porphyry is subvitreous to dull. Siltstone is available in brown, red, reddish brown colors whereas Rhomb Porphyry 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 Rhomb Porphyry are an oil and gas reservoir, as a feed additive for livestock, metallurgical flux, soil conditioner, source of magnesia (mgo).