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 Websterite Uses. We have provided you with all information about Websterite rock here. Websterite is ultramafic and ultrabasic rock that consists of roughly equal proportions of orthopyroxene and clinopyroxene. It is a special type of pyroxenite.. Websterite is available in black to grey, bluish - grey, dark greenish - grey, green, light greenish grey colors. The streak of a rock is the color of powder produced when it is dragged across an unweathered surface. The streak of Websterite is white, greenish white or grey. Get to know more about Websterite rock and characteristics of Websterite rock in the next sections.