The term “Stone Age” is used to refer to early periods in human cultural evolution, and to describe cultures that are seen as “backward” or “primitive”. This attitude can be sourced back to 1877, when American anthropologist Lewis Morgan argued that all human populations progressed through three stages of development: Savagery, Barbarism, and Civilization.
Stone working was a key technology as hominids spread throughout the world, and remained so until the Iron Age, which began about 3,000 years ago. After that, their use started to decline in some parts of the world. Contrary to popular belief, stone tool technology is not simple. It is highly skilled, requiring knowledge of geomorphology, geology, fracture mechanics and the thermal properties of stone.