Chalcolithic

The Chalcolithic (Ancient Greek: χαλκός khalkos "copper" + Ancient Greek: λίθος lithos "stone") period or Copper Age, also known as the Eneolithic/Æneolithic (from Latin aeneus "of bronze"), is a phase of the Bronze Age in which the addition of tin to copper to form bronze during smelting remained yet unknown by the metallurgists of the times. The Copper Age was originally defined as a transition between the Neolithic and the Bronze Age.