Know all about Tachylite and Argillite properties here. All properties of rocks are important as they define the type of rock and its application. Tachylite belongs to Igneous Rocks while Argillite belongs to Sedimentary Rocks.Texture of Tachylite is Vitreous whereas that of Argillite is Clastic, Polished. Tachylite appears Glassy and Argillite appears Rough and Dull. The luster of Tachylite is resinous while that of Argillite is waxy and dull. Tachylite is available in black, dark brown colors whereas Argillite is available in dark grey to black, pink, red, white colors. The commercial uses of Tachylite are cemetery markers, creating artwork and that of Argillite are fire resistant, used to manufracture paperweights and bookends.