The Chalcolithic Age is also known as the copper age. It was a transition period between the neolithic and the bronze age which saw the first use of metals as tools and weapons.
For further reading check the following articles:
|Indus Valley Civilization||Mauryan empire|
|100 Must-Know Facts about Indus Valley Civilization (IVC)||UPSC FAQ|
|Harshavardhana – Harsha Dynasty||Types of Vedas|