Ancient history

Why are no periods of history called the Brass Age or Aluminum Age?

The terms "Stone Age," "Bronze Age," and "Iron Age" are used to describe periods in prehistory when humans used those materials to make tools and weapons. The terms "Brass Age" and "Aluminum Age" are not used because these materials were not widely used in prehistory. Brass is an alloy of copper and zinc, and it was not until the Bronze Age that humans began to use copper and zinc separately. Aluminum is a relatively modern metal that was not discovered until the 19th century.