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 Troctolite Uses. We have provided you with all information about Troctolite rock here. Troctolite is a mafic intrusive rock type. It consists essentially of major but variable amounts of olivine and calcic plagioclase along with minor pyroxene. It is an olivine-rich anorthosite, or a pyroxene-depleted relative of gabbro. Troctolite is available in dark grey to black colors. The streak of a rock is the color of powder produced when it is dragged across an unweathered surface. The streak of Troctolite is black. Get to know more about Troctolite rock and characteristics of Troctolite rock in the next sections.