Know all about Porphyry and Gritstone properties here. All properties of rocks are important as they define the type of rock and its application. Porphyry belongs to Igneous Rocks while Gritstone belongs to Sedimentary Rocks.Texture of Porphyry is Porphyritic whereas that of Gritstone is Earthy. Porphyry appears Dull and Gritstone appears Layered and Foliated. The luster of Porphyry and Gritstone is dull. Porphyry is available in black, brown, colourless, green, grey, red, rust, white colors whereas Gritstone 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 Porphyry are creating artwork, gemstone, jewelry and that of Gritstone are an oil and gas reservoir, as a feed additive for livestock, gemstone, metallurgical flux, production of lime, soil conditioner, source of magnesia (mgo), tombstones.