How are points made?

Chert is hard, somewhat brittle, and it has a conchoidal (shell-like) fracture pattern. When one strikes this type of stone at the proper angle and with adequate force, it is possible to remove a shell-shaped flake. By repeatedly removing flakes, one can shape the piece to create a desired form. Thus, chert breaks in a predictable way; it is brittle enough to be readily shaped when struck with sufficient force; and it is hard enough to make durable tool.

A flint (or chert) "knapper" (to strike smartly) is a person who shapes chert, and other silica-rich stones, by striking them with a hammerstone or bone baton in precisely the right place, at the right angle, and with the right force. This technique, called percussion flaking, is used by a flintknapper to shape a rough block of stone into an oval or triangular object of desired dimensions, depending on whether he wants to make a spear, dart, or arrow point. The stem of the point, that portion of the object that is fastened to a wooden shaft, may be notched and the edges of the point sharpened by using pressure to remove small flakes of stone.

Rob Bonnichsen using a bone tool to pressure flake a point.

This second technique, called pressure flaking, uses a pointed bone tool that is pressed against the projectile point to remove unwanted stone. Sometimes, the flintknapper also grinds the edge of the piece at the spot they intend to remove a flake.

Native American flintknappers use percussion and pressure flaking techniques and grinding to render a rough rock into an aerodynamic missile.