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 Rapakivi Granite Uses. We have provided you with all information about Rapakivi Granite rock here. Rapakivi Granite is a hornblende-biotite Granite containing large rounded crystals of orthoclase which are mantled with oligoclase. Rapakivi Granite is available in black, grey, orange, pink, white colors. The streak of a rock is the color of powder produced when it is dragged across an unweathered surface. The streak of Rapakivi Granite is white. Get to know more about Rapakivi Granite rock and characteristics of Rapakivi Granite rock in the next sections.