General Lithology:Nepheline Syenite Gneiss
Description:An intrusive igneous rock that formed when molten magma rich in sodium solidified below the surface of the Earth, forming the minerals nepheline (grey), sodalite (blue) and cancrinite (orange). The rock has been deformed within the Earth's crust, giving it a gneissic fabric.
Representing:Magma intruded during the Mesoproterozoic Era about 1.3 billion years ago.
Estimated mass (tonnes):0.1