Intrusions

This blocky line of light colored rock is called an intrusion. It juts out from the surrounding rock because it is harder and more resistant to erosion. Intrusions form in the fractures of the main body of rock while it is still deep beneath the surface of the Earth. Hot liquid rock or magma gets pushed into the cracks of the surrounding rock where it then solidifies. Precious minerals are associated with some type of intrusion (dike) formations.