Know all about Siltstone and Chalk properties here. All properties of rocks are important as they define the type of rock and its application. Siltstone and Chalk belong to Sedimentary Rocks.Texture of Siltstone is Clastic whereas that of Chalk is Clastic or Non-Clastic. Siltstone appears Rough and Chalk appears Soft. The luster of Siltstone and Chalk is dull. Siltstone is available in brown, red, reddish brown colors whereas Chalk is available in grey, white, yellow colors. The commercial uses of Siltstone are raw material for the manufacture of mortar, soil conditioner and that 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.