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 Basaltic Trachyandesite Uses. We have provided you with all information about Basaltic Trachyandesite rock here. Basaltic Trachyandesite is an extrusive igneous rock which is a type of Basalt rock and is formed by the rapid cooling of basaltic lava exposed at or very near the Earth's surface. Basaltic Trachyandesite is available in black, brown, light to dark grey colors. The streak of a rock is the color of powder produced when it is dragged across an unweathered surface. The streak of Basaltic Trachyandesite is white to grey. Get to know more about Basaltic Trachyandesite rock and characteristics of Basaltic Trachyandesite rock in the next sections.