Upper Paleolithic tool-makers no longer produced stone tools mostly on amorphous flakes but on blades such as these 24 inch-long examples from the 12,000 year-old site of Etiolles, near Paris. Blades are much longer than they are wide, and many of them are as thin and as sharp as modern knives. Such blades were sometimes made in the Mousterian, but only later were they produced systematically and continuously.
The number of stages between the conception of a tool and its completion was much greater in the Upper Paleolithic than in the Mousterian. This process included the meticulous and time-consuming preparation of the stone core (two Gravettian examples are seen here) from which blades could be struck. Blades were then transformed into the desired tool form by "retouching"--chipping away at the edges with a stone, antler, or wooden hammer.