Rocks are naturally occurring solids which are composed of minerals & have been used by humans since ages. From Stone Age, rocks are used for various purposes. Also, the metals and minerals found in rock play an important role in our life. Get to know all the Siltstone Uses. We have provided you with all information about Siltstone rock here. Siltstone can be defined as a fine-grained sedimentary rock which mainly consists of consolidated silt. Siltstone is available in brown, red, reddish brown colors. The streak of a rock is the color of powder produced when it is dragged across an unweathered surface. The streak of Siltstone is white. Get to know more about Siltstone rock and characteristics of Siltstone rock in the next sections.