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 Porphyry Uses. We have provided you with all information about Porphyry rock here. Porphyry is a reddish-brown to purple igneous rock containing large phenocrysts of various minerals embedded in a fine-grained matrix. Porphyry is available in black, brown, colourless, green, grey, red, rust, white colors. The streak of a rock is the color of powder produced when it is dragged across an unweathered surface. The streak of Porphyry is white. Get to know more about Porphyry rock and characteristics of Porphyry rock in the next sections.