The lunar eclipse happens when the Moon goes through the Earth's shadow. Earth dependably has a shadow, which is made by the Sun. On those uncommon events when the Moon, Earth and the Sun are altogether arranged perfectly, the Moon goes through this shadow.This would happen each full moon if the Moon circled around the Earth in an indistinguishable plane from the Earth circles around the Sun.
Wind erosion is the main cause. And since it is the desert that wind can pick up tiny sand rock particles that slowly grind against the rock. Over time the erosion will give a jagged rock the smooth features as if it had been submerged in a river for the roughly same period of time.
It depends on the cave , but usually c<span>) chemical sedimentary rock</span>