Know all about Argillite and Picrite properties here. All properties of rocks are important as they define the type of rock and its application. Argillite belongs to Sedimentary Rocks while Picrite belongs to Igneous Rocks.Texture of Argillite is Clastic, Polished whereas that of Picrite is Earthy, Rough. Argillite appears Rough and Dull and Picrite appears Rough and Shiny. The luster of Argillite is waxy and dull while that of Picrite is subvitreous to dull. Argillite is available in dark grey to black, pink, red, white colors whereas Picrite is available in black, brown, colourless, green, grey, pink, white, yellow colors. The commercial uses of Argillite are fire resistant, used to manufracture paperweights and bookends and that of Picrite are as a feed additive for livestock, as armour rock for sea walls, metallurgical flux, pottery, source of magnesia (mgo).