Know all about Greywacke and Tachylite properties here. All properties of rocks are important as they define the type of rock and its application. Greywacke belongs to Sedimentary Rocks while Tachylite belongs to Igneous Rocks.Texture of Greywacke is Clastic whereas that of Tachylite is Vitreous. Greywacke appears Dull and Tachylite appears Glassy. The luster of Greywacke is dull while that of Tachylite is resinous. Greywacke and Tachylite 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 Tachylite are cemetery markers, creating artwork.