Like pottery, the typology of the stone tools combined with the relative sequence of the types in various regions provide a chronological framework for the evolution of man and society.They serve as diagnostics of date, rather than characterizing the people or the society.
Bone tools were used during this period as well but are rarely preserved in the archaeological record.
The first most significant metal manufactured was bronze, an alloy of copper and tin, each of which was smelted separately.
The transition from the Stone Age to the Bronze Age was a period during which modern people could smelt copper, but did not yet manufacture bronze, a time known as the Copper Age, or more technically the Chalcolithic, "copper-stone" age.
In Europe and North America, millstones were in use until well into the 20th century, and still are in many parts of the world.
The terms "Stone Age", "Bronze Age", and "Iron Age" were never meant to suggest that advancement and time periods in prehistory are only measured by the type of tool material, rather than, for example, social organization, food sources exploited, adaptation to climate, adoption of agriculture, cooking, settlement and religion.