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 Tonalite Uses. We have provided you with all information about Tonalite rock here. Tonalite is a coarse-grained plutonic rock consisting mainly of sodic plagioclase, quartz, and hornblende or other mafic minerals with phaneritic texture. Tonalite is available in black, brown, 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 Tonalite is bluish black. Get to know more about Tonalite rock and characteristics of Tonalite rock in the next sections.