Stone Age, prehistoric cultural stage, or level of human development, characterized by the creation and use of stone tools. The Stone Age, whose origin coincides with the discovery of the oldest known stone tools, which have been dated to some 3.3 million years ago, is usually divided into three separate periods—Paleolithic Period, Mesolithic Period and Neolithic Period.
In the manufacture of stone implements, four fundamental traditions were developed by the Paleolithic ancestors: (1) pebble-tool traditions; (2) bifacial-tool, or hand-ax, traditions; (3) flake-tool traditions; and (4) blade-tool traditions. Only rarely are any of these found in “pure” form, and this fact has led to mistaken notions in many instances concerning the significance of various assemblages.