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