The Copper Age was a time period between the Neolithic and the Bronze Age. It is also named Chalcolithic (Ancient Greek: χαλκός khalkos "copper" + Ancient Greek: λίθος lithos "stone").
In the Bronze Age, people added tin to copper to make bronze, an alloy which is much harder than either tin or copper. During the Copper Age, this fact became known, but was not much used because tin was scarce.