Risco Blanco is an igneous intrusion being formed by magma (liquid rock) slowly being pushed upwards from deep within the earth. The magma will either solidify before it reaches the surface of the earth (which is an intrusion) or continues to be molten and flows until reaching the surface where it erupts as a volcano (this is an extrusion). Intrusions can become exposed after millions of years. This is caused by the erosion and collapse of the rock surrounding the intrusion - as with the Risco Blanco. 

​

The Risco Blanco igneous intrusion is by far the largest of several such on the island, with a height of 400m the white cliff is visible for miles around. The intrusion is about 3.8 million years old and was originally covered by the older  lava of Roque Nublo. During the last 2.5 million years the Tirajana caldera (volcanic crater) was created by collapse and erosion and the Risco Blanco intrusion become exposed.