Know all about Greywacke and Rhomb Porphyry properties here. All properties of rocks are important as they define the type of rock and its application. Greywacke belongs to Sedimentary Rocks while Rhomb Porphyry belongs to Igneous Rocks.Texture of Greywacke is Clastic whereas that of Rhomb Porphyry is Aphanitic to Porphyritic. Greywacke appears Dull and Rhomb Porphyry appears Rough. The luster of Greywacke is dull while that of Rhomb Porphyry is subvitreous to dull. Greywacke and Rhomb Porphyry are 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 Greywacke are as armour rock for sea walls, petroleum reservoirs, sea defence, tombstones 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).