Know all about Greywacke and Rhyodacite properties here. All properties of rocks are important as they define the type of rock and its application. Greywacke belongs to Sedimentary Rocks while Rhyodacite belongs to Igneous Rocks.Texture of Greywacke is Clastic whereas that of Rhyodacite is Earthy. Greywacke appears Dull and Rhyodacite appears Skeletal. The luster of Greywacke is dull while that of Rhyodacite is greasy to dull. Greywacke is available in beige, black, brown, colourless, cream, dark brown, green, grey, light green, light to dark grey, pink, red, white, yellow colors whereas Rhyodacite is available in black to grey, dark greenish - grey colors. The commercial uses of Greywacke are as armour rock for sea walls, petroleum reservoirs, sea defence, tombstones and that of Rhyodacite are cemetery markers, creating artwork.