Know all about Chalk and Tachylite properties here. All properties of rocks are important as they define the type of rock and its application. Chalk belongs to Sedimentary Rocks while Tachylite belongs to Igneous Rocks.Texture of Chalk is Clastic or Non-Clastic whereas that of Tachylite is Vitreous. Chalk appears Soft and Tachylite appears Glassy. The luster of Chalk is dull while that of Tachylite is resinous. Chalk is available in grey, white, yellow colors whereas Tachylite is available in black, dark brown colors. The commercial uses of Chalk are alumina refineries, creating artwork, drawing on blackboards, gymnasts, athletes and mountain climbers use for grip, in aquifers, paper industry, production of lime, raw material for manufacture of quicklime, slaked lime, soil conditioner, whiting, whiting material in toothpaste, paint and paper and that of Tachylite are cemetery markers, creating artwork.