How stone tools were made?

Stone tools were probably made using two different techniques:

1. The first is called stone on stone: Here, the pebble from which the tool was to be made (also called the core) was held in one hand. Another stone, which was used as a hammer was held in the other hand. The second stone was used to strike off flakes from the first, till the required shape was obtained.
2. Pressure flaking: Here the core was placed on a firm surface. The hammer stone was used on a piece of bone or stone that was placed on the core, to remove flakes that could be shaped into tools.