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 Trachyte Uses. We have provided you with all information about Trachyte rock here. Trachyte is a grey fine-grained volcanic rock which mainly consists of alkali feldspar. Trachyte is available in black, brown, dark greenish - grey, green, grey, light to dark grey, white colors. The streak of a rock is the color of powder produced when it is dragged across an unweathered surface. The streak of Trachyte is white. Get to know more about Trachyte rock and characteristics of Trachyte rock in the next sections.