The occurrence of joints in granitic rocks is interpreted as a result of mechanisms associated with the implantation and cooling of the magma, as well as the deformation caused by tectonic forces to which the rock is subsequently subjected, or as a result of the joint action of pressure relief (removal of the upper layers) and insolation (effect of solar energy on rocks). This last process causes cracks in the outermost layers of some granite boulders, subparallel to the topographic surface, resulting in the flaking that the erosion eventually removes in more or less concentric layers. This type of weathering is designated by spheroidal disjunction or onion-shaped flaking.

In this Natural Monument it is possible to observe granitic boulders with joints associated with the Hercynian fracture plane and granitic boulders in spheroidal disjunction.