The Himalayas are one of the best places to study the mountain building process. The lower area of the Everest massif shows a history of rock that was heated and reheated under extreme pressure. The result is course and crystalline schist that splits easily into thin sheets. Above the schist is a large outcropping of granite, an igneous rock formed under intense heat. This granite is very evident on the lower Nuptse-Lhotse wall.
Granite is light in color and is known to erode in blocks.
Above the granite is a sedimentary rock that, in this case, was formed when material was deposited as sediment to the ocean floor and then was consolidated by the collision pressure. It's shale, limestone, and sandstone. And the Summit Pyramid itself is comprised of a gray, sandy, limestone. It's amazing to think that this, the highest point on Earth, was actually a deep seabed some 325 million years ago.