Hertzian Cone

A Hertzian cone is the cone of force that propagates through a brittle, amorphous or cryptocrystalline solid material from a point of impact, eventually removing a full or partial cone. An example often occurs when a plate-glass window is struck by a small object, such as an airgun projectile. This is the physical principle that explains the form and characteristics of the flakes removed from a core of tool stone during the process of lithic reduction.

This phenomenon is named after the German physicist Heinrich Rudolf Hertz, who first described this type of wave-front propagation through various media.