Know all about Greywacke and Gneiss properties here. All properties of rocks are important as they define the type of rock and its application. Greywacke belongs to Sedimentary Rocks while Gneiss belongs to Metamorphic Rocks.Texture of Greywacke is Clastic whereas that of Gneiss is Banded, Foliated, Platy. Greywacke appears Dull and Gneiss appears Foliated. The luster of Greywacke and Gneiss is dull. Greywacke and Gneiss 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 Gneiss are cemetery markers, jewelry, tombstones, used in aquariums.