RAW_MATERIAL LENGTH_(mm) Chert 10.6 Flint 13.7 Flint 15.2 Flint 15.8 Chert 16.3 Flint 17.9 Flint 19.1 Chert 20.2 Chert 21.2 Flint 21.7 Flint 23.1 Flint 29.3 Flint 30.2 Chert 31.9 Chert 39.1 Flint 39.4 Flint 39.8 Flint 40.0 Chert 40.5 Chert 40.6 Flint 41.7 Flint 42.3 Chert 42.5 Flint 43.5 Flint 44.1 Flint 45.8 Flint 47.2 Chert 49.1 Chert 49.6 Flint 50.5 Flint 91.7