Know all about Greywacke and Picrite properties here. All properties of rocks are important as they define the type of rock and its application. Greywacke belongs to Sedimentary Rocks while Picrite belongs to Igneous Rocks.Texture of Greywacke is Clastic whereas that of Picrite is Earthy, Rough. Greywacke appears Dull and Picrite appears Rough and Shiny. The luster of Greywacke is dull while that of Picrite is subvitreous to dull. Greywacke and Picrite 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 Picrite are as a feed additive for livestock, as armour rock for sea walls, metallurgical flux, pottery, source of magnesia (mgo).