Petroglyphs

 

Petroglyphs are rock carvings made by pecking directly on the rock surface using a stone chisel and a hammer stone. When the desert varnish (or patina) on the surface of the rock was chipped off, the lighter rock underneath was exposed, creating the 

petroglyph.

 

Pictographs

 

Pictographs are paintings or drawings that have been placed onto the rock face. Such artworks have typically been made with mineral earths and other natural compounds found across much of the world.

 

In some societies, the paint itself has symbolic and religious meaning; for instance, among hunter-gatherer groups in California, paint was only allowed to be traded by the group shamans, while in other parts of North America, the word for “paint” was the same as the word for "supernatural spirit".