A technique for making metal artifacts in which the metal is shaped by percussion without heating. Most metals, such as copper, bronze, gold, and silver, are soft enough to be worked while cold. Operations such as hammering and beating could be carried out without any heating to make the metal softer. These softer metals, however, cannot be cold-worked indefinitely because the metal becomes brittle and eventually fractures. It can be counteracted by gentle heating called annealing. Annealing allows crystals within the metal to recrystallize and distribute the stress that has built up. Cold working can then go on until the metal becomes brittle again. Metallographic examination, the study of crystal structure, can give information about the cold working and annealing processes in the last stages of the making of an artifact. Pure gold is one of the few metals that can be cold worked indefinitely without annealing.