Fracturing: Brittleness

Abstract

Most ceramics at room temperature are brittle. That is, they fracture with very little plastic deformation. Many archeologists believe that our very existence depended on the brittleness of ceramics, particularly flint. The fracture of flint, like cubic zirconia, diamond, and glass, is termed conchoidal—producing shell-like fracture surfaces. These surfaces are very sharp and were utilized in early stone tools to cut and shape wood and to butcher animals required for food. The hides were used for clothing and were attached to wooden frames to make shelters. Stone tools were necessary for cutting vegetation and cultivating plants, allowing a change from a food-gathering economy to one of food production, which happened around the eighth millennium bce in southwestern Asia. This revolutionary change from hunting to farming laid the foundation of civilization.