Know all about Greywacke and Oil shale properties here. All properties of rocks are important as they define the type of rock and its application. Greywacke and Oil shale belong to Sedimentary Rocks.Texture of Greywacke is Clastic whereas that of Oil shale is Splintery. Greywacke appears Dull and Oil shale appears Muddy. The luster of Greywacke and Oil shale is 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 Oil shale is available in black, brown, buff, green, grey, red, yellow colors. The commercial uses of Greywacke are as armour rock for sea walls, petroleum reservoirs, sea defence, tombstones and that of Oil shale are an oil and gas reservoir.